From mind to machine

DIY End Grain Cutting Board

2012-01-21T09:02:00.000-08:00

When our counter-top wears out I want to make a full butcher block and wanted to experiment with a cutting board first. So to practice I made a birthday gift for my wife who says she can never have enough cutting boards.

It is rouhgly 10x12 and is 1.5 inches thick. It is much thicker than any of our other cutting boards. It is an end grain design made from oak. The advantage of end grain is that it prevents the knife from dulling as quickly, and makes the board last longer. I started by gluing scrap strips of oak together, letting them dry, and then ripping them on my table saw to the same height. Then I glued them together again. It is finished in two coats of wipe-on food-grade polyurethane. Which is no different than regular polyurethane, but costs more :)

It has circular pieces of inner-tube glued to the bottom to prevent sliding. One thing I did learn from this is you basically need a belt sander to level things; and orbital type ain't gonna cut it, that taks way too long, even of something this small. Here I am cutting some carrots into sticks.

It is now my wife's favorite cutting board by far.

My Home Theater Setup - 5.2 Dolby/DTS

2012-01-16T10:05:00.000-08:00

I figured I show off my home theater setup a little and give some thoughts on what makes a good one on a budget. My setup is by no means the largest or most advanced, but there are some key elements which really matter, and don't have to cost the earth.

I am very happy with my setup and prefer it to the real theater. My objective for a home theater is as a direct a replacement of the real one in terms of its positive benefits.

The Display

The heart of any home theater is the display. The most important thing here is to get a technology that looks good to you, specifically. Not to your friends, not to the sales guy at the store. When I set mine up, the LCD/plasma war was still in full swing. I went with plasma, for two reasons:

1.) Motion on plasma looks fantastic to me. On LCD, I can see the refresh flicker on high-motion scenes (even on the 120 and 240 Hz at the time) and its very distracting.

2.) True darks. Plasma has them. LCD does not. I primarily watch movies, and in a darkened room. I can practically read a book by the dark screen presented by an LCD. It lessens the experience for me.

Here is my 720P display. It is mounted to a real brick chimney using 4 expanding masonry anchors that can take 500 lbs each. The anchors holes were made using a masonry bit and in the mortar between bricks. It uses an aftermarket swiveling mount. Above it I have mounted my center channel.

My display is angled down since it must sit over the fireplace. The most important thing is to put it at a comfortable height you can watch for several hours without neck strain. Plasmas are very heavy so mounting this was a two person job. LCDs are much lighter, and OLED screens are even lighter still.

The next step in a home theater setup is sound. This is the foundation upon which the entire experience is built. It is also why most home theaters leave much to be desired. Splurging on a great screen and skimping on the sound will have you craving the real theater with its high price, lackluster food, and distracting movie-goers. Most of my sound equipment has been custom designed and built to save money.

The Front Channel (L+R)

The most important speakers in a home theater are the left and right front channels, hands down. A great pair of front channels for a stereo configuration only can easily beat a full 7.1 lineup of mid-grade speakers in terms of performance and sound reinforcement. Why? Well, its simple - even in a 7.1 configuration, the vast bulk of program material is still carried by the front and left channels. If they aren't up to snuff, the whole experience suffers, and cannot be salvaged no matter how great your center channel or subwoofer is.

Here is one of my front channel speakers. These have more cost in terms of labor and design work than all my other speakers combined. I designed and built hem almost 6 years ago. For a long time they were the only speakers I had, and they performed quite well.

My right channel speaker. Notice that it presents a fairly confined beam of sound where it sits - this is only ideal for the center couch listening position.

My left channel with / without the speaker cover. The speakers are built from 3/4" solid MDF, and are quite heavy.

Each contains two 6.5" woofers, and a single silk dome tweeter. It uses a second order custom crossover I built myself. These are not simply ported boxes, either - each has two separate sound chambers, with their own external ports, and connected by an internal port. This spreads resonance over a much wider range. Between just my front channel speakers, I have more woofer cone area than a single 10" or 12" subwoofer.

The Center Channel

The next speaker to look into is the center channel. Center channels are important for one thing in particular: dialogue. All dialogue should be anchored on the screen. The center channel can go above or below the screen, I had to mount mine above since there was not enough space between the mantle and the screen. Center channels should provide good, flat response in the range of the human voice. Fidelity is far more important here than power capability.

My center channel uses the same speakers as my front channels, but has a simple ported alignment. It also has an adjustable volume control for the tweeter to get the tone just right, on the back of the speaker.

The center is mounted using an LCD mounting bracket using 5 masonry screw-type anchors that actually penetrate the brick in spots.

The Subwoofer

Subwoofers basically fill the low-end gap that your front channels cannot reach unless they are absolutely gigantic. The other thing they do is explosions, which aren't so much heard as they are felt. To do this, a sub must be able to play to 20hz.

If you have very good front channels, your subwoofer can be focused better on a narrow range of frequencies. I have front channels that can play down to 40 Hz. The means my subwoofer must only take care of 20 to 40 hz - this is set at the receiver. However, do not be fooled into thinking this is an easy octave to cover - it is the hardest, by far. A really terrible sub can go down to 40hz. A better sub can play at 30 hz. A very, very good sub can play to 20hz. Generally, you will not spend less than $500 for such a subwoofer. Keep in mind that part of the price will be the amplifier built into the subwoofer. It will also generally need to be ported, which will make it much larger than a sealed box (twice as big).

My subwoofer construction and setup is covered here. I have two 12" diameter subwoofers in sealed enclosures equalized to 20 hz. This is where I get the ".2" in "5.2" :) This gives me more cone area than a single 15" speaker, and less distortion. I use an external 100W stereo amplifier to save on space and give flexibility. I also built the equalizer itself.

The Surround Speakers

The surround speakers are invaluable for providing and immersive experience. However, they need not be large or capable of low frequency reproduction. They do however, need to be positioned correctly.
If they are not, they are basically worthless. In home theater setups, the surround speakers often present the most difficult problems since they must be located in a walkway, or floating in space.

My surrounds are built into my end-table lamps to sit at the exactly correct height without being a separate decor item. Construction information on them can be found here.

The Receiver

The receiver is one area where you can get great equipment for very little cash. I have an Onkyo. It has worked quite well. Be sure to get a receiver that can do 7.1 (most can) for future upgrades. I'd also get one that has optical inputs if possible - they break ground loops and the cables are quite cheap. Beyond $300 you aren't getting much extra. I'd recommend 70 watts minimum per channel as well, with efficient speakers, this will be plenty. By efficient, I mean greater than 85 dB/w.

On top I have an upconverting DVD player. Blueray players are quite cheap nowadays, just be sure outputs you use are HDMI for video. For audio, optical outputs are best to the receiver. My media center PC has optical out and this is what I use.

I hope this has been interesting and may give you some ideas for your own home theater.

Custom Speaker Lamps

2012-01-15T19:59:00.000-08:00

I wanted to build surround speakers for our entertainment system. This would bring us up to Dolby/DTS 5.2. Unfortunately our couch end tables already had lamps, and would look to cluttered if speakers were placed there as well. The WAF was low on this idea.

So my wife came up with a compromise: build speakers into the lamps. This sounded crazy to me. After pondering for a while, we decided it might be crazy enough to work. So I got to work. I built boxes from scrap plywood, and smoothed them with bondo, and painted them black. I dismantled the lamps, performed some surgery on the connecting rod inside, and wallah...

The lamps have had there middle sections removed and the connecting rods jb-welded into the boxes.

The lamps function normally and have there original power cord. The speaker cord also feeds into the lamp base.

The speakers are 3" in diameter. Not something you will gut much bass out of for sure, but surround speakers aren't designed for that. They are sitting on 12" diameter subwoofers that give me all the bass I can handle :)

You can see the connections into the wall, one set for the sub, one for the surround. I will get to putting banana plugs on them later.

I set the distance and levels for them on my receiver, and popped in The Fifth Element to test 'em out. Awesome! For anyone tempted to go to 5.1, I highly recommend it, it makes movies far more immersive. The cost/benefit is high as well considering how cheaply satellite speakers can be compared to say middle or front channel speakers .They work admirably - now I am just salivating to put some in-walls to go for Dolby 7.2!!!

Cyclone Dust Collection System

2011-12-29T13:38:00.000-08:00

I've wanted to build a dust collector for my tablesaw that is quiet and doesn't clog. Commercially available dust systems cost a fortune.

The best systems use cyclonic separation. This usually is difficult to fabricate for the DIYer. But I built a cyclone separator and relocated the shop vacuum to the attic of my workshop. It uses common parts that are cheap.

First I had to make an adapter for my tablesaw. It had a 4" port. I made a wooden plate to attach the 2" PVC pipe. This pipe is solvent welded.

The vortex seperator is mounted on the wall and constructed from a 5-gallon plastic pail attached to a metal cone made form HVAC ducting. The input and output pipes are jb-welded into place. A bungee cord holds the bucket it place. When the system is on, there is a tight seal created with the bucket and lid.

Here is the pipe that connects the separator to the shop ceiling. I used a hole saw to drill this and put a coupler in place in case I wanted to remove the pipe. My ceiling is insulated so I had to drill a hole in the top as well.

To keep things quieter the shop vac (which is extremely loud) is located in my attic. The shop vac is plugged into a switched outlet for simple wall control, and connects to the pipe. This is a 5HP unit (yeah right). So far no dust actually has made it to the shop vac, which is the whole point of the separator.

I spent about $20 on my vortex separator. The PVC parts and hoses cost an additional $50, but I have a fancier setup that is needed since I wanted it to be quiet, too.

Ghetto Christmas Smoker

2011-12-17T16:53:00.000-08:00

I like both eastern and western styles Carolina BBQ, but I don't like spending too much time futzing around with cooking something. So I made a dedicated smoker from some junk heap parts using my welder. This smoker can not only smoke meat, but it can slow cook a boston butt so it forks apart by just looking at it.

The most irritating thing about doing "low and slow" is controlling temperature over the course of 8 hours. I found this to be important when I previously was doing this on the grill. You get wide outdoor temperature variations - the wind picks up, a cold front moves is, the sun shines, etc. Thus constant tweaking is required to keep the temperature in the correct range, around 212-250 degrees. Since babysitting a pork shoulder is on the lower end of my list of fun things to do, I wanted to automate this.At the most I'd only like to have to change the wood chips a few times towards the beginning, and come back 6 hours later to some succulent, delicious pork.

Notice the combination of the digital PID controller and the welded air tank for a pleasing combination of high and low technology.

The PID controller, hot plate coil and a thermocouple give thermostatic control for unattended operation. The PID along with the solid-state relays that switch the current are enclosed in an old computer power supply. The unit as well as the air tank are grounded for mains safety purposes.

Custom Linkwitz Stealth Subs

2011-08-07T15:22:00.000-07:00

The only space we have in our living room for a subwoofer is under our end tables. Most commercial subs won't fit under them, and if they were small enough, they'd have terrible response. So I decided to build custom subs with 12" drivers that just fit. But you can't simply stick a 12" speaker in a 1.7 cu foot box and expect it sound good. More on this later.

The best material I have access to is 3/4" MDF. A 4x8' peice is around $30 and is enough to do both subs with some left over. That sheet is heavy. VERY HEAVY.

Glued and screwed together with titebond II and drywall screws. This avoids the need for clamping.

A quick check to make sure it fits. It does! The boxes are very long to give as much internal volume as possible. The dimensions are 13" x 17" x 22".

After making the driver and terminal cup cutouts with a jigsaw, I sealed the screw holes with water putty. I have had success with drywall compound in the past, and I imagine auto body filler would work well too. Then I sanded, painted, stuffed the boxes with fiberglass insulation, and mounted the speaker and terminal cup. I used T-nuts for the speaker, I highly recommend them.

Installed and connected, tested to make sure at least sound is coming out :)

As you can see they are pretty stealthy. Just imagine the other one on the other side of the couch :)

So here comes the interesting part. Those 12" speakers have a Vas of 4.25 cubic feet. So how are they not going to sound terrible in a 1.7 cubic foot enclosure?

Well, the magic of linkwitz transform.

This chart explains it. If I stopped here and simply hooked my subwoofer amplifier up to "subwoofer out" on my home theater receiver, I would get the blue line. That's an F3 of 42 Hz. I am missing an entire octave, and my front channel speakers can play that low, which would make the subs basically worthless.

I would rather get the green line, with an F3 of 20 Hz. But how? Adding the frequency dependent gain of the red line, I can reassign the system parameters to make the green line a reality. What is this witchcraft?

Signal processing. I need to create a precise equalization curve that counteracts the terrible response of the system as is. The gain, as mentioned above, is frequency dependent, and goes up as the frequency decreases, but in a very accurate manner. With a "brute force" approach of just increasing the gain at some cutoff, there would likely be a lump in the response, which shows up as "boom".

Here is the magic box I just finished. It makes my subs respond to 20 Hz. In that steel and wood enclosure is a power supply, the linkwitz transform, and +12 dB of gain buffer. I designed and built the transform and gain buffer on PCBs, populated the boards, and installed them. It feeds into the stereo amplifier below it which runs both subs.

I have to be careful as I can probably damage the framing in my house. These subs absolutely thunder when called upon.

Building a Chicken Coop, Part 3

2011-04-10T10:01:00.000-07:00

Part 1 Part 2 Part 3

Once the outriggers were attached, we could proceed to putting the roof decking on, and the sheathing.

My personal opinion is that plywood is superior to OSB as roof decking, thus justifying the additional expense. Plywood is more resistant to impact, and its edges aren't damaged as easily. It also has better fastener pullout resistance. After cutting, some of the smaller panels I could attach by standing up through the rafters on a ladder. Eventually I had to build a scaffolding to get the bigger sheets in place. Once the roof decking was on I started work on the eave and rake fascia, which are made from 1x6 boards. The shed starts to look a lot better once these are in place. I used my air brad nailer to attach the fascia instead of using finishing nails.

Next step was to get the sheathing on. I used 7/16 OSB to sheath the walls. The trick here is to push the structure to get it plumb, then tack the sheathing in place. It is very easy to "rack" the structure when there is no sheathing. I can push it 2-3 inches or more in any direction with my hand easily - since there is not yet any lateral stability. Once the sheathing is in place, the coop became extremely rigid. I had to cut off 1" from each 4'x8' piece to get it to fit under the rafter overhang. It overlaps and is nailed to the lower platform frame as well, which adds considerable strength.

As is standard framing practice, I sheathed over the doors completely, then drove nails through at all 4 corners from the inside, and snapped chalk lines between the nails. Then I set my circular saw to a depth of 1/2", and cut the door out. I left the other door sheathed over as I only need one to get inside for now.

The next step was to waterproof the framing. Its been very rainy this spring, so this step was critical to protect it from damage during the week (when I cannot work on it). There is a specific order that must be followed, however. The first step here was to prime and paint the fascia board, which I did. The reason for this step was the drip edge I need to install overlaps it, and I would not otherwise be able to paint it once that was up. Once that dried, I setup some scaffolding to actually get to the roof.I used 2x4's attached to the sides, and a 2x8 that I can walk on. I got the drip edge on the eave fascias, nailed it in place, and then tar papered the roof on both sides, with my hammer tacker. After the tar paper, the rake drip edge could go on, since it must overlap the tar paper and the eave edge.

At this point the roof is waterproof until I get the shingles on. Tar paper will last a few months in the weather before it degrades from the sun. I went ahead and added the gable sheathing at this point as well, jsut after the following picture was taken.

But the sheathing also needs protection until I can get the siding on, so I began attaching tar paper from the bottom up, to maintain an overlap to shed water. Tar paper comes in 3-foot wide rolls. I needed two rolls to get both the roof and the sides done, although most of the last roll was not used. I'll save it for a future roofing project.

Later I attached some plastic to the door opening to keep the rain out. At least now every time it rains the whole structure doesn't get soaked inside.

Finished up at: http://glenn.hackleman.net/chickens.php

Building a Chicken Coop, Part 2

2011-04-10T09:08:00.000-07:00

Part 1 Part 2 Part 3

After the platform was finished we started on the wall framing. This is where a framing nailer really shines, as you can simply hold to parts together and bam, they are nailed. We marked the top and bottom plates for studs 16" oc. Each wall was assembled on the platform, nailed together, and raised to vertical. Two of the walls were very simple since they had no penetrations. The other two had doors to frame in so took longer and used more wood for the headers and the jack studs. I made certain the doors were going to be taller than 6 feet - most sheds have doors at exactly my height and I end up banging or scraping my head. They are both 6' 4", with one being 32" wide for the main storage entrance and the other 28" for the coop entrance. The walls of this coop are 93", much higher than a standard 8x10 shed.

As we built each wall we raised each into position and tacked them together. Once all were up I squared things up as best I could and nailed them together. Then I nailed the bottom plates to the platform. The last step was to attach a cap plate all around with joints staggered to tie all four walls together.

The roof was made from A-frame trusses with no ridge pole. I built each truss using the rafters with bird's mouth notches for the cap plate, and a single collar tie to reinforce it and prevent the roof from spreading the walls. Cutting was the most laborious part of this process; my framing nailer made short work of assembly. I definitely would want to get a miter saw if I was going to be doing this on any real scale. Once all the trusses were complete, I attached two to poles to get them on the roof, one on each side. I tacked them in place and my wife made a marking pole for the ridge to situate the other trusses and hold them in place, exactly 10 feet long with trusses 24" oc. Once I attached this to the two end trusses, we lifted each into place and after checking for plumb, I toe-nailed each truss to the cap plate.

At this point I am still working on a ladder for everything. Stick framing (as opposed to say timber framing) does not really gain any lateral stability until sheet goods are added. Consequently the structure is pretty rickety - I won't be standing on top of it or anything yet.

The roof framing could have been called done at this point, but I wanted an equal overhang on the rakes as the eaves. So this meant framing in outriggers to support it. I notched the end rafters in 8 spots total, and cut 2x4's exactly to length. In retrospect, I should have done this before erecting the roof, it would have been much quicker that cutting them up in the air with a handsaw.

Outriggers, Lookouts, Purlins, whatever you want to call them - in place. On to part 3!

Building a Chicken Coop, Part 1

2011-04-10T08:52:00.000-07:00

Part 1 Part 2 Part 3

My wife and I have always wanted chickens for eggs. So this early this spring we decided to build a chicken coop and run in our back yard. We have hawks and dogs living nearby so free-ranging really wouldn't work. So we decided to build a strong coop and fully enclosed run to protect the flock.

This chicken coop was loosely based on the ubiquitous 8x10 garden shed commonly available at home centers either in kit form or fully constructed. "Loosely based" might be an understatement, since the only real similarity is that the building is 8x10 feet in size. This turns out to to be a pretty convenient size for minimizing waste with dimensional lumber and panels. Maybe this is why its so popular. Half of the building will be used to house and store their feed, water, and any other chicken accessories, while the other half will be the coop. I planning on automating the feed/water so that the chickens can be sustained for a week or more without intervention. I'd also like to eventually build an automatic chicken door. But I can't be getting to ahead of myself :)

I also designed this coop to be built fairly close to code, as practice for housebuilding (even though code is a pretty pathetic standard in my opinion). The studs (2x4's) are 16 inches on center (oc), and I will be using tarpaper underlayment for the roof, tar paper over the sheathing, as well as aluminum drip edge on the roof. Any doors and windows will have real headers, as well. This will add to the cost and time of construction. The jury is still out on things like flashing for the penetrations, and I don't plan on on the roof framing being up to snuff. There is no requirement for structures of this size to be code built where I live. I was debating on using housewrap, but tyvek is overpriced for this application, and even the cheap stuff is twice as expensive as the tar paper.

First we cleared the leaves and plants in the way and decided exactly where we wanted it. Our back yard has a pretty decent slope with some variability at the site so we did some light soil grading with a rake and shovel to even things out a bit. The 2x6 rim joists were tacked together first to square up the floor and then placed on the blocks. Once square, we adjusted the concrete corner blocks by digging out the soil underneath until they were close to level. A couple of CCA scraps were used on one corner to shim the frame to plumb.

We framed the floor with pressure-treated (CCA) 2x6's. Pressure treated wood is necessarily poisonous to prevent organisms from eating it. It also it highly corrosive to bare steel, which is why I used galvanized nails. We attached 3/4" OSB flooring over the joists. It has tongue and groove construction that helps with strength. OSB (Oriented Strand Board) is an alternative to plywood which is significantly cheaper but offers the same sheathing and flooring performance. Where we live it is about one-half the cost of plywood. It was also secured with galvanized nails since they penetrate into the treated lumber. I put one about every 10 inches.

On to part 2!

stowable workshop attic ladder

2011-01-02T20:03:00.000-08:00

I needed a ladder to get into my workshop attic. However, I hate pull-down attic ladders. They are too flimsy, narrow, scary as hell to go down with both hands occupied, too pricey, and generally cannot bear a lot of weight.

So instead I came up with a plan to build a wider, more stable, and ultimately safer attic access system.

I started with 2x6 rails about 1 inch less than the height of the ceiling, marked and cut slots to make dados for the rungs.

The dadoes are chiseled out one by one with a hammer and wood chisel.

8 to each ladder, 12 inches apart. I discovered after the first rail was finished a much faster method of hogging out the wood using the chisel.

Then I cut the rungs from more 2x6 stock. They are 22 inches in length to give plenty of area when carrying heavy loads up and down the ladder.

Fitting the rungs, some needed some shaving. I put the better sides facing up. No glue. No need. The nails hold things together, but bear no weight.

I put four 10-gauge framing nails into each rung, two per side. Using my new holiday toy. Fast!

Attached to the wall and fully extended. Very stable. No flexing or creaking.

Retracted and stowed. Sits out about 8 inches from the wall.

This is how it is attached. That is a 2x4 ripped in half with spacers glued to form a slot. A lag bolt and washer on each side keep the top captive but allow it to slide down the wall.

about $24 in parts. I'll paint it when I get around to it.

An attic access insulation baffle

2010-12-30T14:57:00.000-08:00

Pull-down attic ladders typically have very little insulation, mine only has a single thickness of rigid polystyrene, while the rest of the attic is insulated to R50. This allows a large amount of heat gain in the summer and heat loss in the winter, which represents wasted money.

So I decided to make a insulated box for the door which is lightweight and movable. The box is made from two layers of foil-faced polyisocyanurate board. This has the highest R-value of any common insulation you can buy, typically R-7 or R-8 per inch.

I purchased one sheet and was able to make this box, which measures 23 x 55 x 9 inches. The board cuts easily with a box cutter and I taped it together with aluminum HVAC tape - not to be confused with duct tape, which is worthless.

Here is my attic hatch open. I built a box of 2x8's around the opening last year, which is strong enough to stand on.

The baffle installed. It fits well, although i will probably make a gasket of plastic sheet around the rim to get it airtight. For now this should lower my heating bill.

Took about an hour in all! Not half bad for $20 in materials.

Installing a Drainage Network, Part 1

2010-10-31T07:40:00.000-07:00

Our house is a ranch, so it has significantly more roof area than a two-story house. This roof area translates to a lot of extra water through our downspouts/gutters when it rains. The problem with this water is that it can end up causing foundation and rot problems, which is the reason I installed a sump pump. I had setup the downspouts to eject about 5 feet from the house with downspout extenders. This partially solves the problem, but we still have an erosion in the mulch around our house, which then turns into a weed problem. So I decided to fix it all with a drainage network. A drainage network is underground piping which connects to the downspouts, channeling all of the water safely away from the house. The first step is to dig trenches for the pipe.

The pipe is 4" PVC sewer pipe. It is much thinner than normal DWV PVC and therefore lighter, cheaper, and more flexible. It still requires fittings, it is not as flexible as corrugated plastic pipe. Speaking of which, why didn't I use corrugated black pipe instead? It is cheaper and easier to install, with fewer fittings. But, the corrugation collects silt and roof particles, and it cannot be cleaned with a pipe snake in the event of a clog - no small consideration when the pipe is not accessible.

There are a total of 3 downspouts connected to this network. The top of the network, near the deck, will eventually be connected to a pipe under the deck which feeds water from a gravel drain area, but that is a future project. All of the joints have been solvent welded to there shouldn't be any leaks.

The network is sloped downward everywhere, I checked all areas with a torpedo level. All of the segments feed into one pipe which will eject into the woods at the bottom of my house. I had to tunnel under a section of my lawn for the last 20 feet. All together I dug and laid 70 feet of pipe.

Next step is to fill the trenches and dig an ejection basin at the bottom of the run.

Installing a downspout drain

2010-10-24T17:50:00.000-07:00

My house is on a slope. As a result I get a fair amount of water against the foundation next to my workshop. Some of the water leaks into my workshop when it rains heavily or for extended periods of time. The drainage runs around the back of my house but that area is flooding now - and that will be a separate project.

So I decided to fix that by installing a downspout drain to divert the some of the water where it won't cause the problem anymore - my driveway. This involved digging a trench, which took a few hours of hard labor. I have clay soil, with lots of rocks. The trench is about 30 feet long total.

Since this is only one downspout from a small roof section, I used 2" DWV (drain/waste/vent) PVC pipe. Normal drain pipe is 4", but that would be a little overkill here. Home Depot only had 4" downspout adapters, so I used a reducing fitting. I discovered thin-wall PVC drainage pipe isn't directly compatible with DWV pipe, but they sell 4" adapters, so I got one.

All of the fittings except for the downspout adapter are solvent welded. The most important thing is to establish a downward slope on all sections of the drain. I used a level and put some large rocks in the trench to prop up the pipe in spots to achieve an even slope.

I then back-filled the trench with the dirt. I sprinkled some grass seed on it to help prevent erosion in the future as well as keep it drier. I purposefully did not tamp it down to give the grass a chance to grow. The fill will settle with time.

Now to see if it works when it rains next. If no water gets into the workshop, its a success.

Double-Sided PCBs

2010-09-26T14:56:00.001-07:00

I decided to try my hand at double-sided printed circuit boards while I was working on my Surround-Sound Headphone (SSH) amplifier. Up to this point all of my PCBs have been single-sided, with wire connections on top to hop traces. Some of the big advantages of double-sided boards are higher board density, fewer wire jumpers, and the ability to easily put surface-mount components on either side of the board.

This is a thin (.030") double-sided board I purchased that can be cut with heavy-duty scissor/shears. The method to get them two sides aligned was putting both sheets of photo paper together, taping the edges, and sliding the board in between. Then I iron on both sides for about 5 minutes. Then I toss the whole shebang into hot soapy water for 10 minutes, and remove the sheets gently. The results:

After etching in ferric chloride, and removing the toner with steel wool, I took a look at the board in front of a bright light source. The traces on both sides line up perfectly! It worked!

I went ahead and drilled the board by hand with my dremel and a carbide drill bit. I have several bits for various holes sizes on the board. Then I populated the board with components, and tested the circuit. I usually start by first populated the power-supply section to make sure that's working, and then move onto the rest of the circuit.

I added a chunk of aluminum as a heat sink for the voltage regulator. It was getting warm during testing. Those wire links are actually supposed to be output resistors, but they ended up not being needed for that section of the amp. The amps with resistors are for load-sharing the current between both sides of the dual op-amps, allowing them to drive lower impedance (16 Ohms, etc).

Only a few top traces were actually needed on this board, so it probably would not have been worth it if I wasn't trying to verify my process. This was a great success, though. Amplifier board for the SSH amplifier complete!

New A/C Condensate Traps

2010-08-29T10:46:00.000-07:00

We started to get a putrid smell in our air system this summer every time the system ran. I figured condensate pan had grown some algae or something so I decided to clean it and the coil. To my surprise the drain pan had several slugs in it, some alive, some in various stages of decay - hence the smell. My system has p-traps on the condensate line, which usually prevent this sort of thing. So I did some research and read the air handler manual. Turns out my traps are too shallow, and didn't meet the minimum requirements specified for installation. *sigh*

I have a draw-through system, since my blower is located after the condenser coil in my air handler. What this means is that my coil/condensate pan operates at a negative pressure, and thus requires deep p-traps to prevent air/water from getting sucked back into the handler through the condensate lines. Shallow traps sputter water back inside the handler, as well as allowing the pan to overflow. Since the traps get sucked empty every time the system turns on, this allows slugs to crawl into the air handler and then they die in the drain pan. Fun.

According to the manual my traps must have at least 2 inches of drop, the old ones have about 1.5 inches. So, I built new ones from schedule 40 pipe. PVC pipe is easy to cut and then must be cleaned with chemical cleaner at the joints, and then put together with solvent cement.

Assembled and glued in the workshop instead of while cramped under the house. Something I learned from past plumbing in a tight crawl space.

Old traps that I cut out with a hacksaw that are too shallow to work properly with my particular air handler.

New traps installed with pipe-dope on the threads. The new traps have 3.5" of drop and more length to store more water. They also have clean-outs on top for inspecting water level, and adding mineral oil to prevent evaporation during the winter when no condensate is produced to replenish the trap.

Before I finished up I hooked up my shop vac on the outlets to suck up and garbage that had collected in the lines. Got a few slugs and a bunch of algae. Then I primed the traps with water and turned the system back on. Both lines are dripping outside just fine now.

Leaking Workshop Wall, Part 2

2010-06-06T21:23:00.001-07:00

After the hydraulic cement I put in in part 1 cured completely, I dried it with my box fan, and purchased some latex waterproof cement paint.

First I wire-brushed the entire area and swept up the chunks. I did this 3 times. Next I put down a dropcloth and put some of the paint into plastic cup with a lid. I did this so I didn't have to keep re-opening the paint can for each coat.

The first coat went on well, and I back-brushed it to get rid of any pinholes or gaps. The paint is very thick and goopy. It took 3 hours to dry, then I added two more coats on 3-hour intervals.

Once the third coat was completely dry I cut a new bottom plate out of pressure-treated wood, and set it with powder-driven anchors that I had used on a previous project. I made two new studs with pressure treated wood as well, and secured them with 2" coated deck screws.

I nailed the plywood back on, and now I just need to wait for a good hard rain to see if I was successful.

Update: It poured down violently tonight, and this spot remained dry as a bone! Unfortunately, a spot on the other side of the wall did not. The saga continues next time, when I fix leak #2!!...

Broken Kitchen Scraper

2010-06-04T18:35:00.000-07:00

I was helping my wife fix some cookie dough for homemade ice cream sandwiches, and I broke her dough scraper. This is not the scraper pictured. She went and got a nicer one at the store(pictured), and then promptly broke it herself. It broke in such a way that I could fix it - one piece fits about a half-inch into the other.

Gluing this would not fix it though, since there would be no way to get as strong a bond as before, and that wasn't enough strength in the first place. So I drilled a hole into both sections.

I cut the head and tip off a 16D steel nail. This will be our reinforcement so it does not break again. If it does break after this we are using the scraper incorrectly.

The parts fit together with the reinforcement rod in place. The trick now is to fill the empty space between the holes and the rod space with an epoxy-type material. I rooted around in my adhesive bin and found some jb-weld.

JB-weld is a two-part epoxy with some sort of reinforcing filler. It is very strong. I mixed these two little beads until it was a uniform grey color. Then I applied it to the nail and assembled the parts.

Then I clamped the scraper in the vice in such a way that it also pressed onto the table, holding the two sections together while the jb-weld cured overnight.

Nice and solid now.

Leaking Workshop Wall

2010-06-04T05:47:00.000-07:00

Every time it rains, a little standing water appears in my workshop corner. I am adding drywall to the workshop (and drywall + moisture = bad), so I decided to finally fix it.

My workshop is an addition by a previous owner. The stud walls of my workshop rest on a short brick foundation wall and for some reason the builder decided to use a pressure-treated 2x8 as a sill plate for this wall, while they foundation and stud wall are one brick/one 2x4 thick. The overhang created is framed with 2x4's and covered with plywood. This framing is not technically load-bearing, as the actual bottom plate of the stud wall rests over the brick which transfers the load to the footing. Perhaps it was done to provide more lateral stability. Or the builder was smoking crack. Hard to tell.

I pulled off the plywood and removed a couple of the short studs, using my reciprocating saw to cut the nails. One of the studs, located at the site of the leak, was rotted halfway through. Mmmmmm...FIBER!

I had to remove a section of the pressure-treated bottom plate to gain access.

After much elbow grease, I ripped it out. It was rotting too, but less so than the stud.
The problem became apparent after I removed a pound or so of dirt/mud that had built up in the corner. When the workshop was added, the new brick foundation wall was only built to within 1/2" of the adjoining foundation wall in the corner. A small amount of daylight is visible at the top of this gap. What I didn't realize till later is this gap runs the entire height of the foundation wall, so about half of it is below soil grade.

I found this out by digging down on the exterior of the wall, where there just happens to be a downspout from a gutter and a poorly interfaced and half-clogged drain tile, which is clearly the source of the majority of the intruding water, and the subject of a future project. Back inside, with the earth excavated, I could then see daylight all the way down to the slab. So much for craftsmanship ;)

After brushing and cleaning the brick on the inside I mixed up some hydraulic cement to plug the gap. The particular brand hardens in 3 minutes after adding water, and is only workable for 90 seconds after mixing. It was a bit warm that day so that cut the working time to 45 seconds. I stuffed it in by hand (wearing nitrile gloves, of course) and used a putty knife to smooth it. I also tamped some into some mortar gaps nearby that may be contributing to the leak.

I dampened the area for 24 hours to ensure the cement fully cured, and dried it with a box fan overnight. Stay tuned for part two of this exciting adventure..

Rebuilding a Carburetor

2010-03-13T13:03:00.001-08:00

Recently we inherited a lightly used lawn vacuum/shredder/chipper combo unit. It is an extremely well-built, high quality machine - I think its about $900 new. It will work great for chipping the branches that fall in our yard and picking up leaves in the fall - we are surrounded by hardwoods :)

When I filled it up, fuel immediately began leaking out of the primer bulb - a LOT of fuel. Sitting in storage for so long had deteriorated the carburetor badly enough to require a rebuild. I sent off for a rebuild kit which was about $20 including shipping.

I pulled off the air filter housing and the gas tank line and removed the carburetor. Gasoline in liquid form is not flammable, and air is not flammable either. The carburetor's job on an engine is to combine the fuel with air to form a combustible mixture.

When I took apart the carburetor the problem was obvious (thankfully) - The float in the fuel reservoir that meters gasoline into the carb was stuck in the bottom position, allowing fuel to freely flow and flood the entire unit. Clearly it had been left full of fuel for year or more, and the fuel had broken down and formed a sticky sludge inside. There is still some on the float in this picture, everything on the inside was coated with this.

I cleaned the inside of the fuel reservoir and the float of the scum using brake cleaner. I used a brass brush. It was time consuming but eventually I got it all off. The picture below is of it cleaned.

Something called a welch plug needed to be replaced and sealed with nail polish. The instructions were written for more than one engine, since my carb was missing a lot of the features described. I also ended up not using half the parts in the kit for this reason. My wife gave me some old polish she doesn't use anymore. While it dried I cleaned the rest of the unit.

I pulled the needle valve and seat off, and replaced them both with new. Here you can see the float reattached, and I am holding it in the "down" position. Its connected to the needle valve and opens or closes it based on the fuel level in that metal bulb reservoir.

Reattaching the reservoir with new grommets and seals.

Where the carb attaches to the engine.

Attaching the carb with a rubber o-ring.

Fuel line needs to be reattached. I thought about replacing it, but its actually in decent shape.

Its a pretty stiff line, and I just needed to be gentle with the gas tank side of the connection, since its plastic and could break if I got carried away.

Attaching the air-filter mount. This has a grommet that came with the carb kit which seals it to the carb housing.

I need to replace the air filter actually since it got soaked with fuel originally. But, the old one will work fine for testing.

Pops into place.

Secured.

Done. I refilled the tank a little, checked for leaks, and then all the way up.

I gave the primer a few pushes and cranked it. It started up, then died. Tried twice more, and it started running good. I vacuumed some of the leaves in my yard and that works great, I also put a few branches through it and they turned into perfect mulch. This thing only effecitvely cost $20!! woohoo!

What this repair has taught me about seasonal maintenance is to be sure to run engines out of gas before storing it for the winter. Otherwise the carb gets gummed up and it won't run.

Fixing Wiper Overtravel

2010-03-12T17:27:00.000-08:00

For a long time (probably a year) my windshield wipers have been smacking into the side post on the drivers side door, and thumping down into the valance at the bottom of the windshield. The constant thump... thwack...was really getting on my nerves. The extra slop in the travel was obviously from some worn part in the wiper drive mechanism. So I finally got around to taking a look..

So I did some research and ordered the parts. About $75 with shipping, but better than the $450+ repair I would be experiencing at the dealer. Once they arrived I began the repair.

The wipers were removed, and the black plastic valence and rubber seal where carefully extracted, their purpose being mainly to divert water away from the engine compartment. Then I took off two bolts, and removed the wiper mechanism.

What isn't shown is how one of the rod arms fell off when I took the assembly out of the car. There's your problem!

Each of these arms translates the rotational movement of the wiper motor into a back-and-forth motion. There are plastic sockets on the ends of the arms which fit over ball joints. The plastic sockets were disintegrating, and causing the slop.

I removed both arms, tossed them in the trash, cleaned the ball joints, and snapped the new rod arms on. The plastic caps came pre-filled with grease. For $75, I'd hope so, since these parts probably cost about 2 dollars to make :)

Back in the car with the new arms - ooh shiny! Bolted it back into place, reattached the valence and rubber seal, and then made sure to "run them" once so the mechanism reset at the normal spot. Reattached the wipers at the bottom of the travel, and problem solved! Now they run nice and smooth. I went ahead and cleaned the wiper blades with vinegar too. It took me about an hour.

Improving Attic Insulation

2010-03-07T05:45:00.000-08:00

Our home is a ranch style on a crawl with an unheated attic. We are darn close to zone 4, which puts our recommended attic insulation at minimum R38, and crawl at minimum R25. The attic is the most important insulation location in any house - it resists loss of heat during the winter by rising air near the ceiling, and prevents hot attic heat from moving down into the home during the summer. It is also accessible, which makes it the most cost-effective place to add insulation.

The majority of our attic has some old blown-in insulation that is pretty dirty at this point, which reduces the effectiveness. We have roof trusses instead of rafters, and the blown-in insulation barely makes it to the top of 2x4's on the bottom of each truss in some places. So we are looking at R11-R15 on a good day.

R30 unfaced rolls were on sale at HD for 30% off. Additionally, there is a 30% tax credit on home insulation products, so I couldn't pass it up. I decided to install fiberglass batts on top of the original blown-in insulation.

Adding the R30 unfaced (no kraft paper) to the attic.

One section completed and now at R40 or higher.

Have approx 24 rolls left to cover the entire attic. I'm glad I installed the attic catwalk system, it makes it MUCH easier.

Attic Catwalk System

2010-02-27T07:26:00.000-08:00

Our roof is supported by trusses instead of rafters, and like most attics, has no floor. This makes relatively simple improvements such as adding insulation, sealing penetrations, or changing electrical fixtures much more difficult. It also makes stepping or falling through the ceiling an eventuality for someone like me who likes to do energy improvements.

I decided to upgrade my attic using 2x4 and scrap lumber to make a sturdy catwalk system. The system is simple - supports are cut, leveled, and screwed into place near the triangular junctions of the truss members. Then horizontal pieces are set in place and fastened with more screws. It is important to use deck screws on the supports, drywall screws are too brittle to safely carry the weight.

Here the 2x4's make up both the supports and the catwalk itself. An additional advantage is this catwalk distributes weight better so that the ceiling drywall finish won't crack.

I used some older lumber I had flying around instead of buying all new.

The catwalk is set approx 20" above the drywall ceiling to give plenty of room for future insulation. In some of the more cramped areas, like shown here, its around 15" above.

Installing a Sump

2010-01-27T12:07:00.000-08:00

Our crawlspace gets a fair amount of water during heavy rains. It seeps through the walls in some places and collects in the corner next to our new water heater. The water level could potentially damage our water heater if it rose to the lower thermostat and heating element. Standing water generates also high humidity which will, over time, contribute to rotting the floor joists. Although the crawl eventually absorbs the water back through the lower wall over a few days, I'd like to rectify the problem before a hurricane makes it a serious problem. So I decided to install a sump.

A sump is a pit dug at the lowest point in an area in which water collects, and when it fills to a certain level, an electric pump empties it out.

I dug a hole in the location where the collected water is the deepest, next to the foundation wall.

The hole is about two feet deep. I filled the bottom with river gravel to level it, while still allowing water to percolate through.

Sumps usually need a liner to prevent them from collapsing, eroding internally, and/or to keep gravel from getting into the pump. Commercial sump liners are at least $30. I made my own out of a 5-gallon plastic bucket I picked up for $2. I drilled 1/4-inch holes all around the bucket so water could enter easily.

The liner is placed in the sump hole and gravel is used to fill in the rest of the hole. This stabilizes the liner and allows water to seep into the liner as the hole fills.

I also added some rocks around the top to help keep things level at the top and prevent a gradient which could erode the clay soil.

The pump itself is a submersible type with a simple toilet-bowl-style float switch. The advertisements about "solid construction" on the box were right - the base is cast iron unlike some of the cheaper models.

A piece of 1.5" PVC pipe serves at the discharge through the house sill plate. There is a one-way check valve on the pipe to prevent water from flowing back into the sump once the pump turns off. I also drilled a 1/8" hole in the pipe below the check valve to prevent the pump from air locking because of the check valve.

I ran a circuit with a GFCI outlet to provided power to the pump. The GCFI helps prevent electrocution, which is always an elevated possibility when electricity and water are involved.

Here is the exterior pipe for the water. Had to use a hole saw on my power drill to get through. This was the most time-consuming part of the install aside from the digging. I had to drill through two joists, the sill plate, a nail, and the siding.

The discharge connects to a flexible plastic pipe that ejects well away from the house.

Tested it with a 5-gallon bucket-full of water a few times, it works great!

Point-Of-Use Water Heater

2010-01-13T11:53:00.000-08:00

Our kitchen sink has always taken a while to get hot water, and with the recent relocation of the primary water heater (adding 60 feet of pipe), and lowering the water pressure with a PRV, the wait is unbearable: about a minute and a half! The onset of winter is aggravating the problem. Since the kitchen sink is probably the most oft-used faucet in our house, I figured a point-of-use heater might be a good idea. It will save water and electricity.

I ended up installing a Ariston GL6 Mini-Tank water heater in the crawl space just below the sink. It would not fit directly under the sink, but the disposal outlet wasn't going to power both at the same time without the breaker tripping anyways.

So I ran an extra 20-amp circuit to the location. It could be 15-amp just the same, but that was the spare breaker installed, so I just kept it 20-amp (I also have a lot of spare 12/2 romex lying around).

I put some concrete blocks down after leveling the dirt. I added some piping for the T&P valve on top, and tapped into the hot water line by soldering some fittings in and using corrugated copper water-heater connectors. Last I added insulation to the connections for efficiency.

Instead of 1 min and 25 seconds, it now takes only 3 seconds for the water to get hot. Success! This unit also serves the dishwasher so it will probably clean better now. Long before the tank runs out, hot water form the main tank will have already reached this little guy.

Wireless LED Throwies Schematics

2010-01-13T09:03:00.000-08:00

Here are the schematics for the wireless LED "throwies". Includes the the power supply as well.

There is considerable room for experimentation.

Installing a Pressure Reducing Valve

2010-01-10T13:25:00.000-08:00

A typical situation that develops in growing areas is a gradual increase in water pressure as the water utility adjusts to serve the greater population density. New homes come with PRVs installed. Older homes don't, and so experience greater faucet and appliance valve wear, increased stresses on pipe fittings, and higher water/electricity bills than when they were first constructed.

We currently have 80psi from the street, and I'd like to try something more reasonable, like 50-60 psi. I recently installed a new water heater with expansion tank which rectified the thermal expansion problem we had. The PRV I chose is a $28 unit from Lowes. It can regulate 25-75 psi, and comes preset at 50 psi.

I bought two 3/4" male adapters to attach it to the feed pipe. If you notice the PRV has a union on one side. This is because you have to solder the male adapters before you attach PRV. There would be no way to spin it to attach both sides without the union.

Here is the cutoff valve for the house. I will be installing the PRV above this on the vertical section. First I start by turning off the valve. I then open all the faucets in the house so i can quickly drain the residual water.

Next I measure and cut the pipe section out to make room for the PRV. About two gallons came out. I have a plastic pail below this to collect it. Water was still sitting in the lower pipe, so I siphoned it out with a piece of vinyl hose from an aquarium store - you cannot solder a pipe full of water.

I clean the pipe ends and fittings with emory cloth and wire brushes, to get to bright, bare copper. Successful soldering depends on this step. The fittings and the pipe ends are then coated with flux, and heated with a MAPP torch. Solder is sweated into the joint and then wiped with a clean rag while still hot.

PTFE Pipe dope is applied to the male threads and the unit is attached on the non-union side first, making sure the flow direction arrow is pointed the right way :) The union is then tightened to complete the connection.

Water turned back on, it works great! The lower pressure should save us about 30% on water bills, and probably 15% on electricity. After a few days of "trials", I will need to adjust the expansion tank charge pressure to whatever value we decide on.

Copper key fobs

2009-12-30T12:26:00.000-08:00

I found some scraps of 12/2 and 14/2 electrical wire while cleaning out the attic, and thought I'd try to make use of it. Short scraps are useless for house wiring.

First need to strip off the plastic insulation.

The grounding wire is bare copper. It's what I will use. Pretty, huh.

A piece of aluminum makes a mandrel, chucked in my cordless drill. I clamped it in my vice and spun it on low speed. I keep tension on the wire using a gloved hand.

Next I use a dremel to cut the rings while they are still on the mandrel. A jeweler's saw would work better since it has a thinner kerf. The kerf with the dremel is wide so when opened or closed the rings do not make perfect circles, but no matter. The copper is too soft for aviation snips, but wire cutter probably would have worked.

The rings have a 3/8" inner diameter (ID). 12 AWG is .081", so I want to calculate the aspect ratio. AR = ID / WD = .375/.081 = 4.6. Full Persian requires at least 5.5, which explains why I was having trouble with the first fob - its practically rigid!

The 14-gauge rings have an AR of 5.9 so work fine in Full Persian. I enjoy working with these copper rings because they are dead soft, similar to silver. Titanium and stainless steel do not share this characteristic.

Relocating and Installing a new water heater

2009-10-27T04:42:00.000-07:00

Our house ~~is fed by~~ was fed by a 38 gallon electric tank water heater that has trouble competing with our Fire Hydrant Presidential showerhead. This is a high-flow showerhead we got from www.takeashower.com and I will shamelessly promote it because its awesome. The tank has been cranked up all the way, and just cannot provided enough capacity for our needs, especially in the winter. We also have high water pressure, which is running the water through the current tank at a ridiculous rate.

The old water heater has no expansion tank, and thus is leaking out of the t&p valve every time it heats cold water up to temperature. We are getting roughly 80 psi from the street, which is the max safe pressure for most residential plumbing. When the water heater recovers after a shower, its skyrocketing to 140 psi until someone opens a faucet. An expansion tank is required to prevent this. It contains a pressurized rubber bladder which allows the expanding water a place to go. Plumbing code didn't require one when this tank was installed.

The other, bigger problem is that it is installed under the house in a location that only gives 48" to the bottom of the floor joists. A large water heater will simply not fit. Armed with my measuring tape, I checked in the tallest location under the house, in a foundation corner. I had roughly 68" in this location - enough for the 80-gallon unit I was looking at (plus piping). Since electric heaters typically have twice the recovery time of a gas unit, I made up for this with more capacity. Two smaller water heaters is another option, but is more expensive.

I started out by digging out the clay in the new location to put in some concrete blocks for a stable base. Leveling would have been easier with the addition of some gravel, but I did not feel like making a trip just to pick some up.

Next I planned out the piping around the heater. Our house has copper pipe, which is relatively easy to work with using sweat fittings. I've found its best to do as much soldering as possible in a well-lit, comfortable workshop, rather than in a crawl space.

So I am building sections as units to avoid soldering as much as possible under the house.

The t&p valve on this tank is located on the heater top, so a pipe is run with an elbow to eject any discharge water safely to the floor.

I made sure to attach dielectric unions to tank inlet/outlet nipples since they are galvanized steel and the house pipe is copper. Without them the unions would quickly corrode due to the galvanic reaction between the dissimilar metals. The dielectric unions have plastic bushings and a rubber washer which electrically isolate the joined pipes.

A little plumber's dope on the union seals the joint when I tighten it to the tank nipples with a pipe wrench. I was pleased that the tank came with heat-block fittings already installed, which prevents heated water from wafting into the pipes when idle.

The new water heater on it's pad. This was a beast to get down there, it weighs roughly 125 lbs empty. It should weigh about 800 lbs full. The expansion tank came precharged to 25psi. After measuring our water pressure (and finding it to be 80 psi, holy crap thats high!) I charged the expansion tank to the same with my air compressor. This is the max the tank can safely take.

I hung two pipes back to to the old water heater location, using copper-coated steel wire hangers. All in all, its about 60 feet of 3/4" diameter copper pipe. There is only one 90-degree direction change in the pipes.

I drained the old heater by attaching a garden hose to the drain fitting.

I had to drain it into a few buckets since the water heater sits below the outside soil level. The valve kept clogging from sediment in the tank. I switched back and forth between emptying these buckets. It was slow-going since its draining from gravity only. Once the tank was drained I cut the cold/hot pipes with a hacksaw and spliced the new pipes into the house plumbing system.

Off of the cold supply union I have installed two ball valves to provide shutoff capability to the heater as well as isolate the expansion tank if it needs service. Ball valves are considerably more reliable than gate valves, open and close with only a 90-degree turn, and it is much easier to to tell if they are on or off.

Once I cut over to the new heater I had two leaks from poor solder joints. They were the first two that I did :) The first I had to cut out to drain the pipe properly. It is not possible to solder a pipe full of water. The second I was able to drain easily and I just added more flux and re-sweated the fitting. I use a MAPP gas torch instead of propane, to solder fittings. MAPP costs several times more than propane but heats much faster, and is worth every penny.

The last step was to wire the 30-amp 220V circuit to the new heater. This was easy since the new heater is next to where the circuit enters the crawlspace.

The problem with running a longer hot water pipe is heat lag on faucets. The time is takes to get hot water to the faucet is a nuisance and waste of money. I plan on over-insulating the hot water pipe back to the original feed, and adding extra to the the branch pipes. Once a faucet has been used for hot water, the water in the pipes will stay warm for longer.

For the cold feed I plan on using cheap polyethylene foam insulation, since I am only need to prevent freezing in the winter. For the hot side I used the more expensive foam rubber insulation, and I plan on adding a layer of fiberglass batting as well.

In the future I am going to add a pressure reducing valve to the house cold supply so I can dial down the pressure a bit. This will make our appliances, faucets, fittings, expansion tank, and water heater last longer.

Ramset Powder-Drive Tool

2009-10-11T13:06:00.001-07:00

I had to anchor a sill plate to concrete for a wall I framed, so I decided to go for a powder-driven tool, I've wanted to try one of these for a long time :) It costs about $20 at Home Depot, and uses .22 caliber blanks to shoot fasteners into concrete.

Since I need to put it through a 2x4 (1.5" thick) and according to the instructions the fastener should go 1 inch into concrete, I chose 2.5" fasteners with a washer attached.

There are three color-coded powder loads available, I chose the hottest (yellow) that the tool took since I was planning on putting it into hardened concrete. Turned out to be a good decision.

Works great! Its pretty amazing that it can shoot through an inch of concrete. Wow.

"Magic Light" for a hall pantry/closet

2009-08-06T19:02:00.000-07:00

We have a hall closet with a light switch on the hinge side of the jamb. Its easy to turn on before opening the door, but also easy to forget to turn it off. What we needed was the ultimate in convenience - a magic light.

A magic light is light which comes on when a door is opened, and goes off when closed. Perfect for pantries or closets which have no windows. Seems simple enough. The hard part is coming up with a momentary, push-button switch that is "normally closed".

I found such a switch in an old computer that was used as a chassis intrusion detector, which sets a flag in BIOS and lets you know if anyone has opened your computer case. For personal use, its probably the least useful feature that a computer's BIOS can offer.

The switch is rated for 125Vac @ 1 amp. Since this switch only turns on a 60W bulb, this is plenty high of a rating (we could do 125W if needed).

I wired some 18 AWG THWN wire to the switch with some crimp-on connectors.

I drilled a slight impression with a large forstner bit to give something for the switch bezel to recess into. Then I used a smaller bit to drill the hole for the switch housing. After I got drilled through the door jamb, I used a spade bit to drill through the stud towards the wall switch electrical box.

Fits well, and the door can close without crushing or putting pressure on the switch housing.

Then I brought the wires up into the existing electrical box using a piece of coat hanger as a hook, and attached them to the screw terminals of the existing switch. Now both can operate the light, however you would never need to use the wall switch again. I may just cover the electrical box with a blank wall plate in the future.

Here's a video of the switch in action:

The last thing I did was seal around the switch with a little white silicone to help hold it in place and stop the slight draft of air moving through it.

Installing steel doors

2009-08-03T21:12:00.000-07:00

One of the first big projects for the workshop is to replace the rear double doors which exit to the back yard.

Currently they are interior grade doors (which are typically hollow and made of thick cardboard) so there is little surprise that they are flimsy and rotting.

For better durability, insulation, and security from zombie invasion, I am installing a pair of steel doors.

I got a prehung set to make life easy. First needed to pop the trim off the old door on the inside. Next I removed the pegboard on the inside and tossed it. This gives me a look at the framing and any adjustments/correction I need to make, mainly to get the rough opening to spec for the new door.

Whoever framed the workshop neglected to use a 1/2 plywood spacer on the header above the door. So I glued/nailed a plywood spacer to the front to bring this up to spec and to give a consistent nail base.

The header is also not perfectly level but not really that big of a deal, the rough opening should allow me to plumb the door.

Now I need to demo the old door and frame. First I detached the hinges and remove both doors.

The frame is nailed into studs so I used my saber saw to cut through the nails.

Then the trim pieces that bridge the gap between the old doorframe and siding are removed.

I left the top at first but later had to remove it too. The frame was broken into chunks and removed as well.

The threshold was unscrewed and removed.

To anchor the threshold the installer had drilled holes in the concrete, tapped in dowels, and used them as anchors. Not exactly a long term solution.

I removed the dowels which were expectantly rotted through a combination of drilling with an old jobber drill and setting a screw and pulling them out with pliers.

I marked anchor holes with a permanent marker on the floor in case I wanted to reuse them later.

Old door totally gone.

I added some strips of plywood/boards to the top of the header and to the side to bring the rough opening to the correct dimension. Got it pretty close.

What I failed to realize was while entire rough opening is racked slightly out of square. The made my first attempt at installing the door fail. The doors would not close properly, and rubbed against each other. We couldn't shim at some spots because there was no room.

So eventually we pulled the door off, and widened the opening horizontally. This fixed all the problems, and only minor shimming was required.

We plumbed the outer door and screwed it into place.

Much nicer door, that is for sure.

My wife re-keyed the knob and deadbolt cylinders to match our house key. She is practically an expert at this now. She also installed the door hardware. I had to mortise the precut spots with my chisel because they were not large enough for our deadbolt.

The next step was hardening the door from physical attack. A door is only as strong as its weakest part. For most doors this is the jamb - you can tell by looking at any door that has ever been kicked in, the jamb usually splinters where the strike plate is. I accomplished this by purchasing decent door hardware - the strike plate is a two-part unit with large brass screws 3.5" long which go through a hardened steel backer. Then the strike plate attaches to that. Should offer better security than just a simple strike plate.

Another source of weakness is how the door jamb interfaces with the rough frame. When you install a door there is almost always a gap here. Inserting strips of wood to fill this gap (particularly at the hinges), then securing the strips with long deck screws, will strengthen it considerably. Its important to use nails as well, as they offer higher shear strength than screws.

The last thing to do is measure and cut the new trim molding for the outside. The brickmold that came pre-attached to the door wasn't going to work, so I popped it off. I was able to reuse the original left and right trim pieces by ripping them narrower on my tablesaw. I did give them a good coat of paint on the back and bottom edge, which should make them last longer.

The top peice however, needed to be wider. So I went down to lowes and picked up a 1x8 peice of pine and cut it to size. I have this two coats of paint on the front, and one on the back, to seal things up.

All the peices are secured to the jamb with my air brad nailer. I absolutely love this thing, and I will be getting a framing nailer soon to complement it.

Some caulking for the siding/trim interface, a little paint, and its done. Pic coming soon.

Beefy Garage Shelving

2009-07-10T06:54:00.000-07:00

The back of our fireplace protrudes into our garage by 2 feet, and makes cubbies on either side. "Cubby" is another way of saying useless space. Some wooden bench-style shelving that extends to the ceiling could make it usable again. Hopefully it will get some of the clutter off of the garage floor.

First I started by measuring the dimensions of the walls and deciding how many shelf tiers would work well. Opaque tupperware-style bins are cheap and durable for storage, so I want to be sure that they will fit. With 9-foot ceilings 3 shelves should work fine, giving 4 storage locations.

I am going to use 2x4 "aprons" for the shelving which will function to transfer the load to the legs and the wall. In this project I am going to use only 2 legs for the shelves for the front, and then the framing in the wall behind as the other supports. So the unit will be built-in instead of free-standing. This has 3 benefits - the shelves will require less materials to build, be secured to the wall to prevent tipping or falling, and give slightly more volume for storage.

The left shelf unit ended up having one front leg otherwise too much of the otherwise small space would be wasted. I used steel joist hangers to attach the 2x4's on the left side.

The rear apron piece is secured to the studs with 3" epoxy-coated deck screws.

Left side with OSB tops attached.

Halfway there!

The right shelf unit is considerably larger and has both front legs for support. Also the top shelf is extended over the fridge to make use of that commonly useless space.

All of the shelf framing is topped with 3/4" OSB which is secured every 4-6 inches with 6D nails. I made the cuts on my nifty sawhorses.

The shelving is very strong, I am able to climb/stand on it with no visible stress, and I cannot pull it off the wall either.

Total cost: $50 - woohoo!

2x4 Sawhorses

2009-07-06T19:10:00.000-07:00

Here are some sawhorses me and my bro built out of 2x4's. They cost about $20. The really unique thing about these is the cleat channels on each one which allow you to rip 8' x 4' sheets without having to lean over the sawhorses. You rip them almost vertically, and each sawhorse holds one of the pieces securely so no binding or snagging of the blade occurs. Seen here is a piece of OSB for the garage shelving.

Attached to the top are 2x3 "sacrificial" strips to protect the top from the circular saw blade when ripping large sheets of plywood or OSB.

They are nice and rigid. I'm glad I built instead of bought them.

New Garage Door Opener

2009-07-06T16:39:00.000-07:00

Our old opener was giving us fits. Its a torsion bar unit so can only pull open the door, not push it closed. Its also only opens if you practically smash your car into it since the remote only works from like 5 feet away. I could probably get it warranty replaced but then I am still stuck with the torsion bar problem. I like positive door control on the way up as well as the way down.

So went and got a fancy chamberlain belt-drive. This thing is cool, it even has a battery backup so you can run it when the power is out. Awsome!

First things first. Need to assemble it. Little bar thing snaps together. And belt goes on. Attach to motor unit, done.

Then need to install the header mount and hoist it up. They gave me wussy mounts, not sure what I was going to do with those, cept maybe wipe my ass with them. I got some beefy 16 gauge angle brackets from Lowes. Lagged bolted it to the overhead studs. In the pic you can see the little mounts they gave me bent out of the way. Pathetic!

Then came time to install the door mount. The two little self-tapping bolt/screws they gave me were a joke.

I grabbed some more L-bracket to reinforce the door and put four 5/16" steel carriage bolts through it. They don't have to be that tight, as the pulling force is "in shear". If they are too tight they will crush the door panel anyways, its sheet metal on both sides filled with styrofoam insulation. Regardless, the door mount is rock solid now.

Installed the safety eyes and door control. Used my staple gun to secure the wires. I severed one wire, somewhere, with a staple. Doh. Had to replace the entire control wire. I reused some of the sensor wire off of the old garage opener, so it was all good. Reuse, foo!

Works great! Door opener was easy to setup, opens fast, is completely quiet, and has very positive control.

Bathroom Vent Fan Install

2009-07-05T15:12:00.000-07:00

The first project was the bathroom fan, because it is noisy, small, and is venting directly into the attic (oops). This is one of those chintzy builder-grade fans that serves solely to satisfy code. I like to call these fart fans because they are for some reason always installed over the commode. This would seem to violate this essence of code which clearly states they are required to prevent excessive moisture buildup in bathrooms, which I would think typically comes from showers, not from last night's spicy enchiladas.

Once in the attic I realized why it wasn't properly vented. Our house is ranch, and the wall it is closest to it is an exterior wall which the roof tapers on. There is no way to get to the damn thing , save chopping a hole in the roof. A midget (ah-hem, little person) could probably do it, but a 6-foot, 210-lb fatass like me can't.

So I decided to find the power feed and sever it at the fan, so I could safely drywall over the old fan cutout and stay code.

The new fan I got from lowes is awsome. It claims 140 CFM, has a 6-inch outlet port, and it virtually silent. It came with a optional reducer to 4-inch pipe, which I promptly tossed in the garbage. The instructions mentioned the reducer as well, and they joined the trash as well. I got an 8-foot length of 6" aluminum ducting and a louvered 6-inch exterior vent.

I had built a ladder for the express purpose of installing the vent on the roof. Scroll to the bottom, you can see the vent in hand.

Installation went well despite roasting myself in the 120-degree attic installing the blower and ducting.

The old fan gets covered by the piece of drywall I cut out for the new fan.

First spackling job turned out like crap:

To spackle correctly you really need decent tools. All I had was an old rusty 4" mud scraper. Went to lowes and got me a tapered 12" mud blade and a mud pan that fits it.

Sanded the big imperfections off and then the second try was spacktacular(har har), at least by comparison.

My wife sanded the final coat and painted it as a surprise one day while I was at work. She did a great job!

Homebuilt 2x4 Ladder

2009-06-19T20:48:00.000-07:00

I need some ladders to get on the roof. Good ladders are like 300 bucks. Screw that. I also need some permanent ladders to access the attic storage on either side of the workshop. I seem like a needy person.

My A-frame ladder is only 8-foot. I got up onto the attic storage from it once and realized I couldn't get back down. That was fun - it was like 90 degrees outside in the shade. That attic was way hotter.

A trip to lowes yielded some 12-foot 2 x 4's and 8-foot 2 x 3's. Then I realized I don't have sawhorses anymore. Son of a...

Some scrap wood outta do. Face-clamped the 2 x 4's (which act as risers) and measured out for notches.

Technically these are dado's. The 2 x 3's acting as rungs will sit edgewise in the dado's for strength. Circular saw, here we go!

They crack out real easy at this stage, and then I clean up the cuts with my chisel. For wood only, dammit.

Look at those pretty notches.

Set these aside, and cut the rungs.

Test fit on the rungs looks good.

Polyurethane glue in the notches. For strength, and its waterproof.

The ladder has rabies. This stuff hardened fast in the heat. Its was 100 degrees outside.

That's a lot of ladder. Should be enough to get on the roof, then it will be converted to a permanent wall-mount ladder about where it is now. It won't be tilted though.

Test run to the roof, the whole point of sweating in the broiling sun building the ladder. It is however about 4-5 degrees cooler where we live than "in the city". In hand you can see the louvered exterior vent I am installing for the new bathroom vent.

See works great for fat folks. Nice and sturdy.

Will varnish it later with some spar urethane.

Wireless LED throwies

2009-05-17T10:23:00.000-07:00

I was digging around in the junkbox and decided to make some wireless LED throwies maybe whynot?

I used a modified ATX power supply, a 555-chopped MOSFET pulled from an old monitor, and coil made from magnet wire salvaged from a blender motor.

The transmitting coil was fabricated by putting some nails into a peice of wood and wrapping to get a consistent shape. When powered by the driver it generates an alternating magnetic field which can picked up by other nearby coils.

Throwie #1:
A a ferrite-core inductor, a diode, a capacitor, and LED. Half-wave only so it has to be right-side up.

Throwie #2:
An RF choke from a vacumn tube oscilloscope, and two LEDs. Rectification is by the LEDs, so it isn't polarity sensitive.

This spider has a choke for an abdomen and the legs make up the bridge rectifier.

Throwie #3:
A coil of hair-thin magnet wire with a diode, and LED. Polarity sensitive.

Throwie #4:
Space ship with bridge rectification from quad 4148 diodes. Very effecient b/c of large receiver and full-wave rectification, works in almost any orientation.

Throwie #5
Spider has choke receiving abdomen and the legs form a bridge rectifier. Four SMD LEDs for eyes in series to cut the voltage some.

Works through paper, plastic, thin metal, etc. Magnetic fields are not stopped as easily as electric fields :)

Here's a clip on the throwies in action:

Finishing the Bench

2009-05-02T07:54:00.000-07:00

I went ahead and gave the bench frame, the top, and bottom an individual coat of spar urethane to increase weatherability.

It took 4 hours to dry, then I attached the benchtop and lower shelf using 1 5/8" drywall screws. I pre-drilled pilot holes like always to prevent splitting. I then used a countersink to leave the screwheads flush.

Next was to mount my vise. For this I used two bolts, nuts and washers for the rear mounting, and I predrilled the front for the lag bolts. Everything was tightened down with a crescent wrench.

The vise secured through the stud on the front and in the rear through the panel. Its very sturdy.

Completed workbench with vise. I will probably give the top and shelf another coat of spar urethane if I feel like it.

Now to build some other projects!

A Patio Workbench

2009-04-26T20:22:00.000-07:00

I decided to make a workbench for my patio and all of my other benches are in storage, as well as being far too large. I really don't need a bench so much as a place to mount my vise. Its hard to work on much without a mounted vise :(

I made a trip down to Lowes and picked up:

5 8-foot 2X4's. The premium kind.
Couple boxes of screws.
A panel saw (all my power tools save the cordless drill, are in storage)

The last time I used a panel saw was when I was under 10. I never really learned how to use one properly, or it was really dull, I can't remember. Regardless, I needed one. Apartment life does not lend itself to the racket of circular or reciprocating saws.

Lowes didn't have much selection, but eventually I settled on 22-inch wooden-handled version from Stanley. It has "differentially hardened" teeth so should stay sharp longer than one without. The tools I used for this project:

The tools and material before the transformation. Astroturf-tastic!

I started cutting using the chairs as a support. I was surprised at how easily the panel saw cut through the 2X4's, and how cleanly.

Without much support the wood chips out when you near the end of the cut.

So I used the cut pieces to form a poor-man's sawhorse.

In about 30 minutes I had a neat pile of wood.

I trued up the peices with my L-square, predilled some holes to prevent splitting, and screwed the them together with 1 5/8" drywall screws.

I made the bench in two L-shaped halves that would later be united.

The bench went together and turned out pretty square. It is very strong and rigid. I used 3 1/2" deck screws for the sides. This was overkill, I meant to buy 3" screws. Oh well.

Now to add the top. Just a test fit for now. This is the thicker 3/4" plywood. The bottom uses 5/8".

Next I clamped the bottom piece to the top and measure out 3 x 5" notches to allow clearance for the legs.

Cutting the notches was quick and easy, the saw worked perfectly and I am getting better at using it.

Notched and ready to install!

Angled it fits right in.

Ta-da! What remains is to screw down the top and bottom, but first give it a coat of polyurethane since its going to sit outside (under a cover, but exposed to a lot of humidity and maybe some splashing from rain).

The bench measures 2 X 4 foot and 32 inches high. I can stand on it and it barely even flexes the top.

Total cost: only $30 in materials. The saw cost $20. But will need that for other projects :)

Now I just need to bolt my vise on...

Post are slow

2009-02-09T12:05:00.000-08:00

And will continue to be that way until I have a workshop again :). We are trying to sell the house, and for staging purposes, the garage now has to be garage again, not a workshop .

Most of my posts will probably be over on gatherer's garden until I get a shop at a new house.

They'll be more "social commentary and philosophical/scientific ranting" than making stuff.

Furnace Thermocouple Installation

2008-12-17T16:36:00.000-08:00

The furnace is complete except for the thermocouple, which makes the controller into a very advanced thermostat. Without it the controller is blind and cannot regulate the temperature. What makes this sensor special is that it can measure temperature up to 2,300 degrees F, or the so-called cone-6 temp for kilns.

Most other devices would have long since melted or burned to a crisp.

The thermocouple works on a principal called the Seeback effect. The junction of two different metals creates a temperature-variable voltage. Each rod is a different alloy of some metal , and are welded together at the tip. A set of double-holed ceramic spacers ensures a seal on the kiln as well as keeps the rods separated.

I had to shorten the thermocouple to correctly fit my furnace. Here it is attached to the ceramic mounting junction.

I drilled a 1/2" hole between the furnace element studs. The studs and related hardware are all stainless steel. I have a rudimentary but cheap method of isolatingthe intense heat from the terminals from the feeder wire to the controller - I used about 3 feet of 14-gauge solid copper wire from a length of romex I found outside on the ground, and made radiator spirals.

I attached the thermocouple wire provided to the mounting block and ran it back to the controller.

The tip protuding into the oven interior by 2". Minimum according to directions is 1.5".

With the controller feed hooked up, and the protective cover in place. When energized these coils will be hot and live with 250V AC.

The completed furnace.

With the door open. I have run it to reach a temperature of 100 degrees. It works well, and regulates. The controller can be set into learning mode to figure out the system parameters and be quicker to ramp up and prevent overshoot.

Now just some things that need to be heat treated :)

Shaping the Handle

2008-12-16T17:22:00.000-08:00

After I let the epoxy dry for a day or so I set to shaping the handle with my new hand-held drum sander.

First I squared it off with sander. I'm glad I decided to use the brass retaining pin. It it much easier to sand away than steel would have been.

I found that using a chisel to carve the wood worked faster, then I used the sander to smooth the lines.

I drew lines on the block to chisel the wood accurately. This wood is red oak, definitely not a forgiving wood for carving. I had to get it really sharp to work at all. I used newspaper and duct tape to both protect the blade from the vise and me from the blade.

The handle is still too thick for a comfortable grip. I removed 1/8" more width after this shot. I sued the 60 grit to get it shape and then smoothed it with the 100 grit.

Shaping done and ready for finish. I am still debating stain or not. It will get a poly finish for maximum durability, either way.

Khukri updates

2008-12-13T07:27:00.000-08:00

The khukri handle modification had some progress over the last week.

I tried to silver-solder the guard on but with no success. Its difficult to get the heat up and even without overheating the flux. I tried several times with no success. If I had a induction heater it might work. So instead I used plumbers solder, which melts at half the temperature. That worked well, and seems to be strong. Then I cleaned up the blade and soaked it in a baking soda solution for 15 minutes to neutralize any residual flux and oxides.

While getting the tang to fit the handle I mulled over the methods I could use to sand and shape it. I don't have much in the way of power sanding tools, at least not in terms of something aggressive. The official knife-makers tool is a stationary belt sander with a 1" or so belt. These take up room and aren't cheap, and most importantly I don't have one. I did however have a few variety packs of aluminum oxide sanding sheets. And some PVC pipe scraps...hmmm.

The Edison bulb buzzed into incandescence: I could make a drum sander!

I cut a length of 1.5" PVC that was two endcaps longer than the sanding sheets. I wrapped a sheet around and marked it for the circumference, then cut it to size with scissors. I then used the sheet to knock the shine off the pipe and give some tooth for the glue to bite. I first thought of using wood glue/gorilla glue/3M 77 spray adhesive..aha! Sprayed both the pipe and the sheet, let them get tacky, and they went together well. Guess I got onto kind of a kick because I made another pipe in 60 grit and two more in 100 grit.

The endcaps where chucked int the lathe and center drilled for 1/4" bolts. I can use the same endcaps for each drum! I wll probably use a peice of wire or a bolt to secure it. I am thinking of either making a "live" handle on the far side and chucking the whole assembly in my power drill, or a mount and chucking it in my drill press.

Once the tang fit the handle inserted the two fiber spaces I was planning on using (felt), clamped it all up, and drilled throuhg the handle and tang. I had a 1/4" steel to use for the pin but steel sands like crap. I needed to use brass. All I have though is 1/2" brass rod, so I chucked it up and turned it to 1/4", chamfering the ends to make it easy to put in.

Then I used a file to make "bites" in the tang, and wrapped the tang in some kevlar fiber to help tighten the tang/handle fit. I then mixed up some 5-minute epoxy, coating the tang, filling the handle, and saturating the felt/fiber washers with it. I clamped again and drove the brass pin through. I left it inside overnight because its a bit cold out for the expoy to cure right.

See you next time, same bat time, same bat channel...

Furnace Door Attached

2008-12-02T07:34:00.000-08:00

Using the frame as a template I built up a box of sorts to contain the firebricks. Some firebrick wedges and extra ceramic insulation keeps everything from jostling around in there, which is good because firebrick is fragile as all hell and likes to fracture. Also the firebricks will fall out the front if not positioned correctly.

I put a hinge on the outer sheetmetal on the door and used metal screws so I could get in to service/replace the firebrick should the need arise. Knowing my luck it will :) I also drilled holes in the oven frame and attached the door hinges using metal screws.

The next step was to cut some of the ceramic blanket to act as a gasket. I cut a piece the correct size, but had to peel it off in sheets thin enough to where I could close the door. It takes light pressure to fully close the door as the gasket compresses slightly, which should help with the seal. It is held in place with nails pushed at an angle into the firebrick.

Check out the impression, thats the seal! I left the middle open for the temperature sensor but decided it shouldn't go there anyways.

I am using a peice of mild steel as a latch for the door, which also activates the interlock switch when closed, allowing the heater elements to energize.

The latch is not heavy enough to push the switch by itself when the door is open.

Last thing I did was mount the controller above the furnace, well away from the door. I've had my face singed by hot air from a household oven, this thing can operate at four times the temperature!

The final two pieces of the puzzle are the element connectors and the kiln thermocouple.

Heat-Treat Furnace Controller

2008-11-29T08:34:00.000-08:00

The furnace controller is complete, all the bits fit into an ATX PS case. It has two safety features to avoid electrocution, as the furnace heating elements, made from kanthal wire, are conductive and therefore pose some hazard.

1.) Since each leg of a 220V circuit is "hot", each pole is isolated by its own solid state relay. I also chose solid state relays because of reliability, and better heat regulation - with an SSR the furnace controller can be configured to switch on/off much more often which would otherwise cause excessive wear to a mechanical relay's contacts.

2.) The relays control terminals are interrupted by a microswitch which I plan to fit to the door latch as an interlock. Any time the door is open, the coils will be switched off, yet the controller will still be on.

I had originally built the furnace frame using galvanized angle iron and sheet. Given the higher temperatures this device will operate at, I didn't want to risk any of it being burned off; zinc is a toxic metal and the fumes will kill you. It probably wouldn't burn off, but I decided to go on the safe side and rebuild the frame after dissembling it and dipping the the various parts into concentrated hydrochloric acid. This dissolves the zinc coating and leaves the metal bare. Since bare steel will rust very quickly (especially if heated!) I coated it with Rustoleum high heat BBQ paint. This can supposedly stand up to 1200 F, so it should work.

The last order of business is the door construction. The door will contain several 2,300F firebricks of the same type as used in the oven, and for a gasket material I will be using ceramic fiber blanket cut to shape.

Electric etching pencil

2008-11-24T12:24:00.000-08:00

Sorry about no posting, if anyone actually reads this blog. Which, I doubt.

After a day of frustrating work on my home-built plasma cutter, I decided to try a much smaller project to take my mind off of things. I got this idea from this article on vintageprojects.com - an electric arc etching pencil. I've been wanting to make this for years now so I can write my name on my tools or label control panels in projects.

I started with a small threaded bolt from my junk box and shrinkwrapped it to prevent the sharp threads from shorting the first layer of the coil as it has only enamel insulation.

The magnet wire is 20-something gauge salvaged from some old toroidal switching cores. I wound the thicker stuff on a larger bolt as an experiment. When I ran out of wire to wind I just scraped of the enamel, soldered on another piece, and kept on winding.

I wound two coils using this method and saturated them with some superglue to hold the windings in place.

The hardest part was finding some material to use for the spring. I ended up cutting some pieces out of a springy motherboard bezel (the part that mates your mobo to the PC case). I drilled a hole for the small bolt and bent the spring into a U shape. I tightened two screws on the core bolt to trap the other end, and attached a peice of 16 gauge copper wire to the small bolt to serve as the electrode.

I wired up the ground clamp and decided to give it a try. It took some fiddling with the gap between the solenoid and the small bolt but it worked! It definitly needed a handle though, as its too small to hold and gets hot. I used a 3/4" wooden dowel and drilled a hole in it lengthwise to press fit the coil.

I can write on pretty much anything conductive. The tip buzzes along as your write and it seems to work best on bare metal, stuff with mildly conductive coatings also works but its more difficult to get a smooth oscillation.

Frankenswitch Part3, Its aliiiiiive!!

2008-08-17T15:06:00.000-07:00

I was mulling over an insulating material to form the base of the knife switch. Wood technically works for the application, but I wanted something a little better on the insulation side, and wood can rot. This may sound hypocritical because my welder case is wood, but i never depend on wood as anything but a structural component. Poking around the house I came up with an old cutting board (a good 3/8" thick!) that my wife hates (woohoo!). I cut it to size and have plenty left over for the second switch.

The handle is scrap plastic and held to the blades with some metal screws. I greased the pivot points with some high temp grease, and there are lock washers to set the tension as it wears. Given this isn't going to be a high use switch, I imagine it will last forever.

The handle design prevents this from being used for live applications - your index and ring finger come into contact with both poles when it is operated. This is to be placed under a rotating panel in my welder to facilitate polarity and ac/dc switching applications when the welder is switched off. Sticking your hand into an operating welder chassis is a good way to get dead anyways so that covers that.

The second switch should take a lot less time since I was designing as I went on the first one.

Frankenswitch, Part 2

2008-08-15T21:13:00.000-07:00

So I bought some more copper pipe at Home Depot to make the center poles for the uberswitch.

Cutting the pipe is easily accomplished with a pipe cutter. This one came with my MAPP torch. MAPP torches are similar to propane blowtorches but they use methylacetylene-propadiene to provide a hotter flame. I need a hotter flame because I do brazing occasionally, which occurs at much higher temperatures than soldering and propane doesn't have enough moxy.

The cutter is placed on the pipe and spun around it. The blade is tightened every few revolutions, and thats all it wrote. Helps avoid crushing the pipe or coming up with an uneven cut.

Now that I have the pieces and I start flattening them on the anvil. I found that rotating to balance out the blows helped avoid scars from the hammer edge.

Going slow gives me better feel. I keep flipping the piece to even out the stress.

All flat. Its easy to thin the copper in one spot if you are really laying into it.

Getting too late to cause more racket so I drilled the other contacts for bolts with my drill press, it has big old humming induction motor that is smooth and quiet.

Tomorrow I will fold the center poles and solder them up. Looking at what I've made so far gives me the impression that it will be able to sustain much more than 200 amps. We'll see.

FrankenSwitch, Part 1

2008-08-14T20:32:00.001-07:00

I need two honkin' DPDT switches that can sustain 200+ amps for my arc welder. They are for AC/DC and polarity selection. So I am building some of the type shown in the monster films - knife switches:

No worries, they will be under a cover and therefore shielded when energized.

In this episode will be constructing the pole clips.

Got a length of 1/2" copper water pipe, cut it with a pipe cutter, and hammered it flat. Copper is very malleable and ductile, so this is relatively easy to do. I wore ear muffs because it is loud! Then I bent pieces in vice with hammer to form the clip components:

Soldering copper pipe is not hard, but there is a process. First, I cleaned the copper with soap and water to remove oils. Then I used a wire brush on the parts until they are shiny. Next, I applied flux with a clean chip brush - ideally you use an acid brush, but I didn't have one:

I had to arrange my vise and these vise-grips to keep it all together as I soldered it with MAPP torch. Soldering copper involves heating the center or far side of the joint, and then letting the joint melt the solder on the near side. The solder wicks into the joint and flows to wherever there is flux.

After soldering I washed the clips at my sink under cold water and then soaked and rinsed them in a solution of baking soda and water to neutralize the residual flux. Flux should always be cleaned off after any soldering, brazing, or welding operation. Flux is highly aggressive and will corrode the shit out of damn near any metal. The finished clips - they are now very strong and quite heavy:

What is left is to drill holes for terminal bolts and mounting screws. Next on the list will be the throws (knives) and the center support poles.

more to come...

Brake repair on the TL

2008-05-28T08:48:00.001-07:00

I have a 99 TL and the rear driver brake indicator (or "screamer") has been going nuts for the last few days. After I pulled off the tires I found the rotor was warped and the pads were down to nubbins. After pulling the caliper I figured out why - the caliper was frozen and the brakes had been dragging on that wheel. It must have overheated and warped the rotor.

So picked up a new caliper, thought about rebuilding my current but who wants to deal with that?

Going to install the new one tonight. The core charge on the caliper is $70 (yikes) so will be bringing that back to carquest, most definitely :)

After installation and some headache found that a few companies are marketing the incorrect rear brake pads for my car. There are some little tabs that poke up and DEFORM the piston on my brand new caliper (grrrrrr). So I made a shim out of some scrap aluminum. Fixed the brake squeaking and uneven wear.

Sometimes making something is faster than buying it. Especially when its midnight.

IR Remote Control Extender

2008-03-27T09:32:00.001-07:00

I needed to run an IR signal between rooms and didn't want to cough up the $50 for a commercial extender.

Most parts are scavenged or what I had laying around.

The basic premise is to use a IR decoder module that strips out the 38-40kHz carrier and turns it into a logic signal, then let that gate a 555 timer running astable at 40kHz.

The IR module I had runs active low though, so I had to setup a transistor inverter to bring it to active high. The inverter out runs a transistor hooked up to a red LED to indicate when signal is being received. It also runs to pin4 of the 555 (reset pin) which when low will drive the 555 output low regardless of state. Some long wire running into the other room is terminated by an IR LED. Voila! The circuit runs of a wall-wart and contains a 5 volt regulator (LM7805) and reverse-polarity protection diode.

Works, can't complain :)

Building Custom Speakers

2008-02-22T16:16:00.000-08:00

Anyone looking at a decent pair has probably realized that great-sounding speakers typically don't come with such a great-sounding price tag. DIY can cut cost by avoiding the manufacture AND retail markup, which can be 300% or more of the actual cost. This pair is an MTM design for a Home Theater front channel.

So crack open a cold one, and lets build this sumbitch.

The miracle of table saws turns this 3/4-inch MDF:

Into this:

After glue, screws, and some cursing:

Marked the cutouts and drilled pilot holes for the jigsaw:

Avast, ye landlubbers, thar be holes. Now to attach rear baffle and cut more, ye scurvy dogs.

Side project: had to fabricate a brass bearing on the lathe to make my 3/8" rabbiting bit work for 1/2" as well:

The router creates dust and as a side-effect some rabbit joints for flush mounting:

The ports tubes are 2" PVC pipetuning the box to an F3 of 40Hz, and angled to provide for centering of the holes:

Now to repeatedly spackle and sand imperfections and screw holes, watch out for my spackle-fu:

Soon to come:

1.) cherry veneer it up somthin' good.
2.) Finishing said cherry veneer
3.) Put all the gubbins in.
4.) Enjoy that sweet, sweet sound/piss off nosey neighbors

Hacking phone wiring for FastEthernet AND phone

2008-02-21T12:53:00.000-08:00

In most recently-built homes the phone wiring is run using CAT5e or Cat6e cable. These cables have 4 pairs of twisted wire for a total of 8 wires. A POTS (plain Old Telephone System) phone requires just 2 wires (tip and ring). Therefore we usually have 3 pair running through the walls completely unused.

Most phone wires are also run in a star topology, which is an easy conversion to "poor-man's" structured wiring.

FastE requires two pair (4 wires) to work:

**Ethernet 10BaseT (Twisted Pair)**
Pin #	Signal Name	Function
1	TD+	Transmit Data
2	TD-	Transmit Data
3	RD+	Receive Data
4	NC	No Connection
5	NC	No Connection
6	RD-	Receive Data
7	NC	No Connection
8	NC	No Connection

Only 1 pair is used for phone, so its easy to convert the whole house to use Fast Ethernet without running any additional wiring.

It should be noted that Gigabit Ethernet in this fashion would not be possible, because GigE uses all 4 available pairs in a cat5e or 6 cable. See below:

Ethernet 1000BaseT (Twisted Pair Pinout)
Pin #	Signal Name	Function
1	BI_DA+	Bi-directional pair +A
2	BI_DA-	Bi-directional pair -A
3	BI_DB+	Bi-directional pair +B
4	BI_DC+	Bi-directional pair +C
5	BI_DC-	Bi-directional pair -C
6	BI_DB-	Bi-directional pair -B
7	BI_DD+	Bi-directional pair +D
8	BI_DD-	Bi-directional pair -D

So how does one go about doing this? Well, its simple, really. Buy RJ11/RJ45 wall plates like, and wire the pins according to the T568A standard below:

Standard, Straight-Through Wiring (both ends are the same):

RJ45 Pin #	Wire Color (T568A)	10Base-T Signal 100Base-TX Signal	1000Base-T Signal
1	White/Green	Transmit+	BI_DA+
2	Green	Transmit-	BI_DA-
3	White/Orange	Receive+	BI_DB+
4	Blue	Unused	BI_DC+
5	White/Blue	Unused	BI_DC-
6	Orange	Receive-	BI_DB-
7	White/Brown	Unused	BI_DD+
8	Brown	Unused	BI_DD-

Pins 4/5 or 7/8 can be used for your phone jack. It really doesn't matter.

On the other side of the cable, the same thing will need to be done.

Jumping Ring Project

2008-01-09T18:52:00.001-08:00

Ever since I saw one of these in grade school science class I wanted to make one. Its just a coil of wire with a mild steel core made from thin steel rods. If AC is applied an aluminum or copper ring should jump off the end. The core isn't solid to reduce eddy currents when AC voltage is applied.

For now I'm testing it on DC - 12V @ 8 amps, I need more turns to ensure that the breaker wont blow if I hook it up to mains. I did pull an AC relay out of an old microwave so I can use a low-current momentary SPST as a "dead man's switch".

It picks up screws and steel hardware just fine. It also attracts other steel ojects, as you can see from the video :)

Need to come up with a base to contain the switch, fuse, etc. and point the thing up.

How to turn a Gurkha Khukri into a camp knife

2007-12-30T15:27:00.001-08:00

For Christmas I received a Gurkha Khukri - these can be had from BUDK for around $18.99.

The handle is wood, and it came with two pathetic little skinning(?) knives and a cheap goatskin sheath. Pretty rough diamonds as is, but the knife is a solid base for a very useful camp/field knife project. The blade is nearly 1/4" thick carbon steel and the interior curve gives the knife some awesome chopping power. It also has a full-length tang which is great for strength. Because it's so inexpensive I also don't feel too bad about potentially screwing it up on a custom project.

The biggest drawback as it comes is the handle - very uncomfortable. As a result that is the first thing to go.

Here is the wood I am going to use for the new handle. It is rubberwood. It is a very dense, hard, tight-grained wood which should be perfect for a knife handle. This block is part of a coffee table leg set which needed shortening in our house.

First I cut the block down the center to form the two scales for the handle using a coping saw. The cut is not perfect, but the scales will be flipped inside out and shaped and sanded on the cut side, so there is no problem.

Then I mounted the knife (sword??) in my vise with a rag to prevent scratching. I drilled out the rivets with a 1/4" cobalt drill from one side.

There is some sort of cheap red/brown epoxy filler stabilizing the scales and filling in any imperfections in the handle. I got a chisel in there and pried them off fairly easily.

The pommel is more difficult to remove. I used a screwdriver and worked it back and forth until it was loose and popped off. Took some coaxing and time.

As you can see the tang will require reshaping. I intend to give it a more graceful shape.

More later...

Mig welder : part 3

2007-11-19T19:32:00.001-08:00

The more I think about it, the more I get the idea that it may be better to build a seperate, portable MIG welder that can run on 120V/20amps and save the space I left in the Arc welder for a future TIG attachment. Fortunately, this change of plans will not result in wasted time/effort.

Reasoning:

1.) The constant current of the arc welder is exactly what you need for TIG anyways.
2.) I could add a variable current footpedal easily to the arc welder for TIG.
3.) TIG uses different gas (argon) on things that TIG is good for (aluminum), so would need another bottle for gas anyways.
4.) Having a portable MIG would be sweet.
5.) I didn't build a spot for the gas canister on the arc welder. Yet.
6.) The arc welder is effin heavy.
7.) Being able to run a MIG on 120V would be really, really nice.
8.) There's easily enough room in the arc welder for an arcstarter, also essential for TIG.
9.) I can wind the trannies for the MIG at the exact voltages I need.
10.) Its soooo easy to convert ATX power supplies to work for what I need on the MIG, but retrofitting the arc welder would be a pain in the ass.
11.) The MIG would be much smaller/lighter, and I can make completely from metal easily.

The only real disadvantage is that I need to scrounge at least 3 more MOTs. I got one today, so..

MIG Welder: part 2

2007-11-11T16:47:00.001-08:00

After building my ATX lab supply, I used it to test out my MIG wire speed controller setup.
I think I'll go ahead and use another ATX supply as the accessories supply for my welder.. its just so easy to do.

Seems to be working, the voltages and motor operation seem right when either arc voltage or target voltage is varied. Won't really know though until its installed and tested in the entire MIG welder application.

ATX Power supply into a cheap lab power supply

2007-11-11T16:31:00.000-08:00

This is old hat by now and is covered in some web articles. Why build it? I needed the +/-12V to test my welder wire speed control.

Basically an ATX supply scavenged form an old computer, cut off all the wires, install a load resistor, and an LED power on indicator + switch. Good source of ~1 foot lengths of 16 gauge wire as well.

You get +12V, -12V, +5V, -5V, and +3.3V from this supply. The 5V is at ridiculous current - usually 25 amps or more. 12V is usually 15 amps+!

Super easy to do, surely the cheapest way to get a fairly capable lab power supply.

I used terminal strips - most people use binding posts. It's all I had on hand. The REALLY nice thing about computer power supplies is that they are over-current protected. If you draw to much, it just shuts off. Turning it back on, and it is reset.

High Voltage DC Power Supply

2007-11-01T11:20:00.000-07:00

This circuit generates 10-20kVDC depending on the input voltage using a rectified flyback transformer typically found in Computer CRT monitors. It is suitable for driving HV loads such as Marx Generators and Lifters.

Here is a video of me testing the HV supply - notice that I am only using one hand!! This is good practice even though the current in this case is too low to kill me.

The basic circuit is a 555 timer running astable around 17-18kHz, wired to a Power MOSFET which chops the supply voltage wired to the primary of the transformer.The power MOSFET is a low resistance type (IRFP450) to keep heat dissipation to a minimum. This will reduce the heatsink requirements substantially.

How to arc weld

2007-10-27T12:42:00.000-07:00

I am using my homebuilt arc welder, it is capable of about 180 amps, has infinitely variable heat control, and I am building a MIG welder into the same chassis!

This may be the blind leading the (soon to be) blind, but .......eh. Here's a clip of me welding a practice bead - notice I had to tap the end of the rod to expose the metal (the flux coating burns slower than the metal rod, creating an inverted cone on the end if you stop welding before the rod is used up.

The ultra, ultra cut down lesson..

1.) Safety - Liquid metal spraying, high current electricity, noxious gases, intense UV light, woohoo! Good ventilation, long pants, long sleeves, gauntlets, and welding helmet are needed.
2.) Ground the metal peice (no galvanized!) with the grounding clamp. Pop an electrode in the rod holder. Turn on Arc welder, set amperage to whatever.
3.) Strike the arc, either like a match, or "jabbing". Otherwise it will stick, and eventually the rod melts like a string of butter.
4.) Keep the rod (it's always getting shorter) same distance from work as rod diameter. Run a bead along the metal.
5.) After is finished, chip that slag off with chipping hammer and observe that crappy weld!
6.) Get out the angle grinder and grind it off so you can practice more.

MIG Welder: part 1

2007-10-15T10:25:00.000-07:00

Now that my arc welder is done, my journey to the dark side is almost complete.

The MIG attachment is simple in theory, but there are a lot of things to make for it.

The electronics are split into four parts:

1.) Arc voltage sensor board - Conditons measured arc voltage, generates error signal from difference in actual voltage and target voltage, and provides speed voltage for next board.

2.) Voltage-controlled PWM board - based on voltage from arc sensor board, run motor at between 5% and 100% of rated speed at 12V using Pulse-Width Modulation.

3.)MIG relay board - has relays for welding current, wire feed, and gas valve. Both the wire spool and gas valve and be independantly engaged to allow for wire spooling and gas purge. All activate when the MIG trigger is pulled.

4.)12V+/12V- Power Supply - Provides the power for the other boards, since the arc sensor uses opamps for analog addition/subtraction, the voltage needs to be able to swing below zero.

The PWM, power supply, and relay board are tested and work. I haven't rigged up something to the arc board to test it yet.

Steel pop-up table mechanism

2007-10-15T10:18:00.000-07:00

At home I have a coffee table sitting in front of our couch and our TV. Also, we have a DVR. These two ingredients result in a fair amount of dinners on said coffee table. It would be nice to have them table height. So, its time to make the coffee table a pop-up type.

Google on pop-up table mechanisms cost about $160...eeek.

Time to fab one up with my homebuilt arc welder.

1/16" 1" squre steel tubing and 1/8" steel flats make up the frame. The rotate points are 1/4" bolts.

Only two inches, high, good enough to fit my table with little modification!

Dead Batteries Suck

2007-10-12T20:57:00.000-07:00

I went out to my car this weekend after work to drive and get a bite to eat, and found engine chattering when I tried to start. I ran a check on the battery with a voltmeter and during cranking it was dropping from a decent 12.5V down to a whopping 4V. Bad battery? Oh yes.

So, it needed jumping.

How to jumpstart a car:

1.) Park good car near enough to bad car so that jumper cables can reach between the batteries, and open the hoods of both.
2.) Hook both read jumper clips to each red (positive) battery post on both cars.
3.) Attach black jumper to good battery negative post.
4.) Attach other black jumper to bad car metal chassis (engine block, unpainted bolt, etc) AWAY from bad battery (this is to avoid sparks which may ignite the hydrogen produced when charging a battery).
5.) Start good car. Rev it around 3-4k RPM for about 30 seconds.
6.) Start bad car.
7.) Remove black jumper clip on bad car, then on good car.
8.) Remove both postive jumper clips.
9.) Let bad car run for 30 minutes. Do not need to rev it, it will not charge any faster.
10.) If you have a Voltmeter measure the voltage at the battery posts while the car is running and the rear defroster, high beams, and heater fan are running. Less than 13.5 volts, your alternator is history.

In my case the car would not start on its own even after charging. Battery is a goner- need a new one!

If you change it yourself be sure to bring the old back to the place where you buy the new to recover you $10 core charge. Plus it helps the enviroment, if you give a flying shit. Mainly it saves you 10 bucks. And its probably illegal and a pain in the ass to dump it. So please, save a tree.

After a reader posted about saving water from lead I would like to start a rant.

Above, I am being sarcastic. Notice, that almost all old car batteries are recycled. This is because quite simply, a core charge exists. People in general do not give a shit about the enviroment - you have to make them give a shit by making in financially lucrative to do so. If it costs people time or money to save the environment, then it won't happen. Showing a bunch of bullshit National Geographics on saving the earth on TV isn't going to save the environment. IT will make people feel good, but it wont help. In fact, the power used to watch such films will, in essence, continue to destroy the enviroment. I am tired of people patting themselves on the back about recycling or "saving the enviroment" while they still burn incandescents in there home. Compact Flourescents use 1/4 the power, which saves 75% on your electric bill..which helps the environment. And you save money.

I actually care about the enviroment. I've spent enough time on 50-mile backpacking trips and camping to realize that we need to preserve what we have around us. What I don't care for, at all, is folks who are into recycling, "saving the enviroment", etc just because its hip and chic. This leads them to save it in the least efficient way (or worse, harm the enviroment more) and when the fad is over, they quit. Its kind of like those folks with the support our troops and breast cancer ribbons on there cars - stop advertising your doing it, becuase 10% of it went to the cause, the other 90% to the ribbon - just give your money to the foundation directly and stop bragging.

The rest of us are saving money, doing 10 times what the fakers are to save the enviroment, and getting cool tax breaks because of it.

A core charge is a good idea. A deposit on cans and bottles, is a good idea. Compact fluorescents are a good idea.

If you saved money, you probably saved the enviroment.

DIY Arc Welder finished

2007-08-29T18:43:00.000-07:00

I painted the metal side panels on the welder green with industrial rustoleum paint. Turned out okay, and at least now they won't rust.

Observe my awsome inability to focus the camera!

I grabbed some cheap organization brackets from HD and riveted them on. Lets me wrap the welding cables and the power cord for easy transport. Welder is mounted on casters, it weighs 160 lbs.

Welder porn. Here you can see the diode bridge, choke, SCR (with heatsink!), SCR PWM controller, AC power distribution block, and fans. The two upper side panels are on hinges for easy access. The other side innards can be found in an earlier post with the shunt and welding cable polarity selection - it is failry empty now but will later contain the wire spool and wire feed assembly/motor.

Butt-shot with the input for 220V @ 50amp, and fans. Fan guards keep blades protected on rear side of fans.

I've decided to call the arc welder portion complete for now - at some point I will make the cutouts for the volt/ammeters but they aren't essential for operation. Notice there is plenty of room left on the front panel for those and additional indicators and switches, etc when I add the MIG section.

These welding cables are really overkill for this application - these are 0 gauge! But they aren't dropping much voltage, that is for sure :)

Lower panels are held on with bolts and wingnuts. The MOV transformers occupy the lower section - 3 on each side for a total of six. Forced air cooling by fans pulls cool air from front of welder, over transformers, and out through the back fanset. Air cooling from upper section is drawn in through rear and mixes with lower section at the front. The combination increases overall air velocity.

Replacing a Car Radio

2007-08-22T19:50:00.001-07:00

When my trunk CD changer croaked last month, it was the last straw.

Let me explain why-

1.) My head unit is the one that came with the car - a combo tape / CD deck. A well known and rather effin annoying manufacturing caveat of this particular model is the inability to play CD-Rs. Grrrrrrrr.

2.) Another well-documented and much lamented "feature" is the complete and total lack of an AUX input on this reciever. Oh wait, no thats not technically true. I can spend $100 on a blueIceWhatthefuckeverjazzyjeff adapter just to get AUX INPUT. Really? is that all?

So...when the only means of listening to my own music went into the trash with my CD changer, decided to cough up the green for a new car stereo reciever. I ordered a new one from crutchfield, and spliced the adapter for my car to the new one for the head unit.

Tomorrow I will be ripping out the old and slapping in the new. This one has USB drive capability, mp3, the whole nine. Even has an ipod cable if I were into that sort of thing.

Above is the result of one hour of listening to airbase and soldering.

The little yellow widget is a resistive mixer I soldered together for the stereo "pre/subout" RCA jacks on the new receiver. Just three 10k resistors in a Y configuration. This will give me a mono signal for the subamp in my trunk, and prevent shorting of the two L+R pre-outputs. I will be coating the whole shebang in epoxy later.

The extra-long green wire on the splice-job is the amp turn-on wire, terminating to a spade plug. This way if I ever decide to add an amp I technically don't need to rip out the dash again, since I will have the pre-outs and the amp turn-on wire available under the glove-box.

DIY Arc Welder - Adding DC part 2

2007-08-20T20:22:00.000-07:00

The rectifier bridge and the choke are installed and correctly wired. It occured to me that I may need to explain how I constructed the rectifier bridge, since it looks complicated.

It's really not - how it works can be found here. The basic construction consists of four 100-amp diodes with independant heatsinks wired in the configuration explained in the article. I tapped the heatsinks and bolted the rectifiers on. A liberal application of arctic silver heatsink paste was used to ensure good heat transfer. Then the heatsinks were attached to an insulating plastic base which is attached to a wood plate I varnished for longevity. All this effort is to ensure that the heatsinks do not short circuit on each other or anything else, and remain firmly in place when vibration, heat, etc are present.

You may be wondering, isnt this welder capable of more than 100 amps? Won't this exceed the diode current ratings? Ah! the secret, look back at the wikipedia entry - only two diodes are actually on at any given time, so the average current works out to be 100 amps for each diode even if the welder is providing 200 amps! The diodes also have a peak repetive surge current rating of 200 amps, no there should be no problem. I actually would have bought beefier diodes but these were a great ebay auction at only $20 for all 4 - couldn't pass it up.

I have measured the output voltage and it is now indeed DC.

I also recieved a voltmeter and ammeter to monitor the power output of the welder when welding. This will also help me gauge how well the voltage-sensing MIG wire controller is working when I build it. I bought a beefy 200 amp shunt to provide the 50mV to the ammeter to measure the current.

The shunt is pictured above (its the large thing in the lower right corner), and is mounted with fiberglass strips to keep it isolated from the wooden chassis. It is inline with the welder's grounding cable.

Shunts are curious- they are just big resistors that work by providing a very precise and low resistance (basically a short) but even shorts have a measurable resistance. All resistance causes a voltage drop, and this particular shunt is designed to provide a 50mV (yes, milla-volt) drop when 200amps passes through. 50mV just happens to be the full deflection range for an analog meter element. So if we hook these two tiny screws up to a meter, it will deflect proportionatley with the current. If the meter has a 200amp scale printed on it, this will tell us how many amps are passing. Cool, eh?

The main thing to remember here is that we are working with ohm's law. Since we know two values, we can calculate the third.

Fully deflected,

50mV
200A?
Resistance=?

V=IR, so R=V/I= 50mV/200A=.00025 ohms....or 250 nano-ohms.

Not much eh?

In fact, you can see the calibration notch on this shunt in the lower part of the black strip in the middle (it is a thick copper strip painted black). Some technican built this thing, and then hacksawed it a bit to get it juuuuuust right. So why so low a resistance? Well mainly, we want to minimize how much power is dissipated in the shunt. Power = Volts * Amps, and a larger resistor will result in a larger voltage drop.

DIY Arc Welder - Adding DC part 1

2007-08-09T06:59:00.001-07:00

I wound the choke for the arc welder. 6 AWG wire on a microwave oven transformer core. I got about 15 turns on there. Hopefully it will be enough. If I have to add another I am going to run into space problems in my welder.

Just need to install it and the rectifier bridge now. If all goes well I will be arc welding with DC current shortly.

Advantages: smoother arc, smoother welds, easier to strike, better penetration, easier to learn with.

Disadvantages: "Arc blow" if welding magnetic or magnetized materials. Remember that a welding arc is a plasma, so it is susceptible to magnetic fields. It will "bend" in line with the magnetic flux, and possibly quench. AC arcs don't have this problem as they switch polarity 60 times per second, so they just vibrate a little.

If a powerful enough field were present the AC welding would fail too. This phenomenon was employed by Nikola Tesla to produce magnetically quenched spark gaps.

The light of a 1000 suns..or just 1.5?

2007-08-08T13:42:00.000-07:00

Ok a little slow on updates. Its not like I am getting paid to write, and with comments turned off I have no visibility on hits, so I might as well be speaking to a vacuum.

So I turned comments on.

I built the heat treat oven, but it has no door. The control box hasn't been wired either, but I have all the parts. I am going to use two solid state relays instead of one, need to cover both LIVE poles of the 220V outlet, since the heater coils will be electrically hot otherwise, even when the oven is off. I need to get working on the damned door, its where the thermocouple mounts as well.

The Arc welder is finished, and finally there is light! I welded a crappy bead on a large bolt I had laying around with 1/8" 6011 rod, first I had the power turned all the way down so it was just sparking and sticking to the bolt. I cranked it up to max and burned through most of the rod - worked like charm. It was hot wearing full jeans, a buttoned up jean shirt, leather gloves, and that arc helmet out in the humidity, but the proof of concept is over. Time to mount the rectifier bridge I made and wind the choke, which will put me into the area of DC welding.

I have actually been custom designing the voltage-controlled variable wire speed circuit for the MIG welder portion, I originally made a PWM circuit thats just knob speed controlled, but since my power supply CC not CV, I need some way of regulating the voltage, MIG being a CV process n' all. Arc voltage to high, feed wire faster. Arc voltage too low, feed less wire. Now I have a knob for the target voltage (10-35V for MIG) and the wire speed will vary to obtain that voltage. In theory.

In essence I am designing a closed feedback loop system, but since I slept through "Elements of Control" in college, I am flying blind. Although I am not worried about oscillation, mainly at pulling a clean DC voltage signal off of the arc with some sense wires at the gun. The circuit looks good on paper, but I imagine some RF will ride in on those wires - I may have to wind some chokes and clip on some ferrite beads to block it. Since my measuring circuit is analog (opamps) optoisolation is way too complicated. Anyways, the opamps do the comparison, shift the level a bit, and provide a DC voltage to the PWM section which is voltage-controlled.

I'll have to test it at some point to see if the circuit goes apeshit or not when its measuring a real arc.

DIY Heat Treat Oven

2007-05-27T07:36:00.000-07:00

I've started work on a Heat Treat oven for heat treating metal parts.

It will be run from 240 AC and features two kanthal heating elements, a PID temperature controller, and the refractory will be firebrick. Max temperature: 2,300 Degrees F.

I also aquired a Microwave/Conventional Oven wall mount combo off of craigslist for free, and I stripped off the microwave part. Luckily there was not much integration between the two, just a relay to faciliate timed bake, which I bypassed. I wired a 240 plug to the unit, and it runs fine, just need to make an enclosure for the controller.

I already made a dolly for it. I think I will build the HT furnace and mount it on top of the conventional oven. This way I can temper parts right after quenching them. I can also use the conventional oven as a powder coat oven, and for bake-on paint finishes.

Project plans

2007-05-27T07:19:00.000-07:00

I have a few projects in the queue, and am waiting on parts for now.

The first is an arc welder. I've also made this most progress on this so far. An arc welder is in essence a low voltage, high current power supply. I've seen arc welders that are just banks of car batteries (hey it works!). I am using MOT (Microwave oven transformers) to meet this requirement. MOTs are high voltage transformers, but they cores are beefy, spicy and typically rate at 1kw or more, so by cutting off the high voltage secondary I can then wind a few turns of heavy gauge wire, "transforming"(har har) them into a high current, low voltage supplies.

The first stage of this project is an arc welder. Later, I will be constructing a DC rectifier, Wire Feed system, and gas cylinder with solenoid to make a MIG (Metal Inert Gas) welder that uses this arc welder as a power supply.

Pictures and updates, soon!

Thread turning in "action"?..(har har)

2007-01-07T16:23:00.000-08:00

I had to cut some threads for a custom single shot bolt action I am working on.

This is and IMI Timberwolf .44 Magnum barrel. I stepped the chamber slightly and put 1.36" of 18 tpi threads on. You can see the extractor slot which was already cut. I simply threaded over it, but I will be using it in my design for extraction purposes.

The major and minor thread diameters give me a chamber thickness of between .126"-.159".

The barrel has no taper and is .796" in diameter, 18.5" long.

2007-01-06T11:17:00.000-08:00

New Tools for Christmas!

1.) A 2HP, 8 Gallon compressor from HF. Had to put nearly 40 ounces of compressor oil into this thing to get it full. Kindof a pain, but so-called maintenance free, oiless compressors aren't going to last nearly as long. Works great, and opens me up to the world of inexpensive air tools. Some definites are a sand blaster gun, HVLP paint sprayer, and brad nailer. I'll probably build a powder coat gun for it as well.

2.) Drill Bit sharpener. Drill doctor, Model XP2. Awsome, simply awsome. Even puts split points on bits if you want. I sharpened a few cheapo HSS bits first - razor sharp and drill great. Don't know how I lived without it. It works on my cobalt bits too, which dull up fairly quickly given I am often drilling into hardened steel and cast iron. They are required, as HSS bits, even TiN-coated ones, won't even start a hole on some stuff I work on.

You'll put your eye out with that thing

2007-01-02T06:08:00.000-08:00

Flails were originally used seperate wheat from chaff, but like many medieval-period agricultural tools, eventually developed into a specialized war implement. They came to be known as morning stars, holy water sprinklers, etc. Basically, a handle, a length of chain, and a smooth or spiked ball. Their puncturing, crushing effect was useful on armored opponents where swords may be less effective. They were also considerably easier to build.

I made a morning star for my bro (for christmas), he's into swords and knives and likes to shop from the bud k catalog. So I decided to write up what I did in case anyone wanted to make one too.

The shaft is made from oak dowel, stained and polyurethaned, and is capped with cast iron pipe fittings. The fittings were screwed onto the wood dowel and for the top one I drove several long screws deep into the dowel to expand it out into the pipe fitting. The decals on the pipe fittings have been ground off, nothing screams "unauthentic" like CHINA imprinted on your weapon. I wrapped the handle in leather string soaked in more poly to keep it rigid and waterproof. The spiked cylinder is made from 2" diamter 1018 cold rolled steel, drilled to accept the spikes. I chose a cylinder because sourcing steel balls of sufficient diameter was difficult, and I don't have the ability to cast metal.

The spikes are 4130 chromo bar turned in my lathe, and I hardened and tempered them too. This is easy to do - first I started with a foot-long peice of 1/2" 4130 which I cut into 8 equal sections with a reciprocating saw fitted with a metal cutting blade. Then I tapered them to cones on my lathe. Heat treating simply involved holding the spikes in my vice grips and heating till it was cherry red, then quenching in the hot brine solution (hot tap water and salt). At this point they can scratch pretty much anything, but are very brittle. So they had to be tempered by sanding back to bare metal with some emory cloth, and then heating them back up until the oxide colors appear. I stopped at blue (spring temper) and allowed them to air cool. I decided to also leave the oxides on for effect.

The chain is galvinized and I brazed it to both ends with silver brazing wire. The method was as follows - I cut the chain to length with bolt cutters and drilled holes to fit the U-shaped peice of chain I had left to both sides. After a little grinding, I cleaned the drilled parts and the chain peices with WD-40 then acetone to get all the grease off. Then I coated them with flux, and hammered the half-links into the holes I drilled in the peices. Heating it up to a light red heat, the silver solder flowed into the gaps and gave a nice strong bond. I cleaned the flux off with a wire brush and kerosene afterwards to prevent any rusting.

Then I simply jb-welded the spikes into the cylinder head and fitted some metal rings I found around them for effect. The JB-Weld had to be carefully added to one side of the spike before it was inserted, otherwise an air-piston effect ocurred and the spike could not be pushed in flush. Smearing it only on one side allowed the air bubble to escape and the spike to fully seat. The spiked cylinder is attached the chain via the metal plate and 4 bolts, which I had to drill and tap holes for. Before tightening it all down, I smeared JB-weld on both surfaces to give good adhesion and more strength.

After it was all done I lightly coated the metals parts with some poly to keep rust away.

It goes without saying that actually using this thing is pretty dangerous - if one were to swing and miss your intended target, you'd probably get spiked in the face or crotch - that'd be no good.

But, it is built strong enough for actual use.

Internal threading on a lathe, part 2

2006-09-30T09:15:00.000-07:00

Now that I have external and internal threading tools ground at proper angles, I decided to thread and custom fit two parts. I'm not working off of standard diameters(hence custom), but have decided on 16 TPI (turns per inch) as the thread pitch, with the standard 60-degree acme threads.

The first thing to do was change the gears in the headstock of the lathe to give 16 turns on the chuck for every inch that the carriage moves.

Then I turned down the diameter of the male part and bored out the inside of the female part so they would mate with the thickness of the threads in place. I left a shank of sorts on the male part to give a defined area for the threads to be cut.

Usign the external threading tool, I threaded the male part, and then used the internal threading tool on the female part. The quick-change tools made the process so much faster - it was amazing.

The internal tool takes a long time to cut because deflects a fair amount. The shavings also tend to ride in the threads and you need to blow them out after every cut.

At one point I thought that it had been ground incorrectly, because they looked squarish. I was worried that perhaps the tool was rubbing the newly cut threads. It's actually hard to see the internal threads - there exact profile is nearly impossible to judge as the pattern creates a rather frustrating optical illusion. I used a thread gauge to check, and it seemed to indicate that I was doing okay.

In the end, the parts screwed together with very little play. I was very happy with this - I was half expecting to break the tool or ruin the the threads by engaging the half-nut at the wrong point or disengaging it during the cut.

Internal threading on a lathe, part 1

2006-09-30T08:46:00.000-07:00

I was right, the internal threading tool was the hardest to grind of all. I could have ground all of the other tools I have made before in the time it took me on just this one. Of course, the first time doing something is always the longest. I sacrificed a broken parting tool to make it.

The difficulty stems from a few things:

First, you have to remove a gargantuan amount of metal. The most, easily, out of any tool. Grinding dust gets everywhere. I also had to dress the grinding wheel several times during the operation to bring back its cutting ability with the diamond tip dressing tool.

Second, because the tool is thin and not much metal is left, the tip heats up very rapidly. So you must be more mindful of cooling it. This is less of a burn hazard and more of loss of temper/hardness problem. I once read somewhere that modern tool steels don't suffer from hardness loss after excessive heating from prolonged grinding. This statement assumes one thing: that we are grinding a normal tool with plenty of surrounding metal, which will conduct it to your fingers and become unbearably hot, thus requiring a trip to the water cup. A tool with a thin shaft will NOT do this fast enough and it is easy to get the tip of the tool orange hot, with NO HEAT INDICATION on your fingers. This will ruin the temper on the tool tip, as indicated by an extreme softness of the steel even after it has been cooled in the water cup. If this is the case you must grind off the soft spot until hard metal is again reached.

Third, grinding the inside angle of the tip is not easy as it requires holding the tool at an extremely awkward angle that puts your hand frighteningly close to the spinning wheel. I have not yet come into contact with a spinning grinding wheel, and I don't ever want to suffer the experience.

The end result:

It definitely aint pretty, but it works.

Toolage

2006-09-30T08:28:00.000-07:00

Today's update includes the arrival of a few new tools!

1.) Quick-Change Tool Post

The QTCP was smaller than I had orginally thought, but works great! It came with 4 attachments: 2 normal tool holders, a cutoff tool-holder, and a boring bar holder. Once mounted you can switch tools in a matter of 5 seconds. Also, the tool individual tool heights can be dialed in with a nut so that no shims are required to get the tools centered on the work!

2.) Carbide boring bar set

Grinding boring bars from tool blanks takes a long time (even more so than parting tools), so I ordered one of those inexpensive boring bar sets. The feature steel shanks with carbide tips brazed on. There are multiple lengths in multiple thicknesses. This allows you to select one that is the thickest possible for a given hole to minimize tool deflection.

3.) Cutoff tool

Cutoff tools (parting tools) are also time consuming to grind because a lot of material needs to be removed to make one. So after all that effort either it breaks or its not long enough to do the job. (sounds like the voice of experience) This cutoff tool is nice becuase it can be adjusted to multiple lengths and if the tip breaks off you quickly regrind it.

4.) Center Gauge

A center gauge is required if you want to be able to grind blanks into threadcutters. You need a precise 60 degree angle, and its not easy without a reference. So you grind a little, check the tool, grind a little, and check the tool again. It's also useful for keeping the tool perfectly perpendicular to the work.

Grinding and some threading

2006-09-14T20:42:00.000-07:00

Finally (successfully) cut some threads on my lathe! They are 24 tpi on a peice of aluminum.. and some random diameter since I am just trying to get the process down.

The hardest thing to figure out was the gearbox changes to drive the leadscrew at the correct speed. Since this is a mini-lathe there aren't any of the nice gear selector levers or anything. So I poped off the gearbox cover and fiddled with it until I figured it all out.

The first time I tried I wasn't using the threading indicator, I was just trying to back up the leadscrew between each pass so as not to lose my position. The tracking was off - I suspect that changing the leadscew direction offsets the alignment. So I just turned down the botched threads and started over at a slightly reduced diameter.

This time I actually used the threading dial indicator, which works perfectly! Duh. I put a light line on the peice, stopped the carriage, pulled back on the crosslide to clear the peice, cranked the carriage back to past the end, set the tool .001 deeper, and engaged the leadscrew at the designated mark, 1-8 in this case. The tool tracked perfectly! I repeated 5 times, and ended up with this:

I didn't make the tool sharp enough so I ended up with squarish threads, but the boint is, it worked! By the time I was done I was shaking from excitement. I don't have a center gauge yet so its hard to grind the tool at 60 degrees, but I'll get one before I try any serious work. The next logical step is internal threading, which should not be harder save grinding the tool. Here are all the tools I've grinded so far:

From left to right: A cartridge rim cutter, a parting tool, a ~60 degree external threading tool, a boring tool and a double-sided roughing/finishing tool. An external threading tool would look a lot like the boring tool but be thinner to provide relief for the little cutting "finger" that would need to be ground at 60 degrees. It seems like it may be the hardest tool to grind of all :)

Longer toolpost bar and carriage lock

2006-08-28T09:07:00.000-07:00

I added some lathe modifications this weekend. Made a longer bar for my toolpost to give more leverage, and drilled and tapped a hole on the carriage to install a copper cylinder as a carriage lock. As you can see the toolpost bar is rusting, but hey it works. When I decide to parkerize something I'll throw it in with the mix and be done with it. Until then it adds character ;). You can also see the carriage lock - its the little allen wrench below. A 60 degree turn on that locks the carriage solid for facing operations, making it much easier to get a smooth, flat finish.

While I had the carriage off I lubed and adjusted the leadscrews, one was gritty and is much smoother now. I used white lithium grease. I have a monster tube of it that should last me for a million years. I use it to lube the gear train in the headstock too, it really cuts down on the noise and wear.

Boring bars....yawn

2006-08-28T08:16:00.000-07:00

I am building a flash hider for an AK-style rifle from mild steel. It is a slip-on sleeve design with set screws. I haven't decided on the port geometry, but I have no mill or end mills to cut slots so it may end up being more of a muzzle brake than a flash hider.

The largest drill bit I have is .5". However, the female hole accepting the muzzle has to be .550" in diameter. Instead of going out and buying bigger drill bits or boring bars and holders, I decided to try making my own from what I had lying around.

So last night I ground a boring tool from a 5/16" tool steel blank. After the grinding dust settled, I was left with this:

My main concern was that the tool shaft is very hard but brittle so might break easily during use. I imagine that boring bars are somewhat flexable to reduce breakage (Although this this would cause more deflection, but there must be some balance) So I kept to .002" cuts max. I used a fair amount of cutting oil as well. There was no chatter and the tool cut smoothly. It was pretty exciting.

Now I see the value of carriage stop - when boring it is difficult to tell how far the tool has gone, as it is inside the workpeice. If it goes to far, especially after multiple passes, the tool with dig in and most likely snap. I dropped a cylinder of copper onto the v-groove on the ways to act as a tell-tale. It worked, and I disengaged the half-nut just before I reached it, going the extra mm or so by hand with the carriage handwheel, and "felt" for the start of chatter.

From Mind to Machine!

2006-08-21T10:46:00.000-07:00

First post on my own machining/welding/metalworking/electrical/electronics blog.

I recently purchased a Cummins 7x12 minilathe. I'd also like to buy a MIG welder and a milling machine to round out my tool collection, but that will have to wait - they aren't cheap. I'm planning on making improvements to the lathe as I go. This first thing I did was mount it on a peice of melanine, and then I fabricated a chuck key from bolts as the one that was supposed to come with the lathe exited via a large hole in the side of the box during shipping (I guess).

My next purchases was a 6" bench grinder, to grind lathe tools. It works well on the 5/16 tool blanks I bought. My first lathe tool was a simple turning tool. It worked, albiet badly. I'm getting better though.

I also purchased a 115-peice cobalt steel jobber drill bit set - nothing pisses me off more than a dull drill bit. These should last a long time ( a long time being longer than 5 seconds hopefully).